diff --git a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/StepRegistry.java b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/StepRegistry.java
index 291682eec..c3e857c38 100644
--- a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/StepRegistry.java
+++ b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/StepRegistry.java
@@ -22,8 +22,9 @@ public interface StepRegistry {
      *
      * @param jobName the give job name
      * @param steps   the job steps
+     * @throws DuplicateJobException if a job with the same job name has already been registered.
      */
-    void register(String jobName, Collection<Step> steps);
+    void register(String jobName, Collection<Step> steps) throws DuplicateJobException;
 
     /**
      * Unregisters all the steps of the given job. If the job is not registered,
diff --git a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/DefaultJobLoader.java b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/DefaultJobLoader.java
index 9c0d44dbf..d5d52f0df 100644
--- a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/DefaultJobLoader.java
+++ b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/DefaultJobLoader.java
@@ -181,6 +181,7 @@ public class DefaultJobLoader implements JobLoader, InitializingBean {
 				if (unregister) {
 					logger.debug("Unregistering job: " + jobName + " from context: " + context.getDisplayName());
 					jobRegistry.unregister(jobName);
+                    stepRegistry.unregisterStepsFromJob(jobName);
 				}
 
 				logger.debug("Registering job: " + jobName + " from context: " + context.getDisplayName());
diff --git a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapJobRegistry.java b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapJobRegistry.java
index 14e2271ea..b4cc29e9c 100644
--- a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapJobRegistry.java
+++ b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapJobRegistry.java
@@ -77,7 +77,7 @@ public class MapJobRegistry implements JobRegistry, StepRegistry {
         return Collections.unmodifiableSet(map.keySet());
     }
 
-    public void register(String jobName, Collection<Step> steps) {
+    public void register(String jobName, Collection<Step> steps) throws DuplicateJobException {
         stepRegistry.register(jobName, steps);
     }
 
diff --git a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java
index 8fb4348a0..d4d4dffc2 100644
--- a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java
+++ b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java
@@ -1,6 +1,7 @@
 package org.springframework.batch.core.configuration.support;
 
 import org.springframework.batch.core.Step;
+import org.springframework.batch.core.configuration.DuplicateJobException;
 import org.springframework.batch.core.configuration.StepRegistry;
 import org.springframework.batch.core.launch.NoSuchJobException;
 import org.springframework.batch.core.step.NoSuchStepException;
@@ -23,17 +24,20 @@ public class MapStepRegistry implements StepRegistry {
 
     private final ConcurrentMap<String, Map<String, Step>> map = new ConcurrentHashMap<String, Map<String, Step>>();
 
-    public void register(String jobName, Collection<Step> steps) {
+    public void register(String jobName, Collection<Step> steps) throws DuplicateJobException {
         Assert.notNull(jobName, "The job name cannot be null.");
         Assert.notNull(steps, "The job steps cannot be null.");
 
-        unregisterStepsFromJob(jobName);
 
         final Map<String, Step> jobSteps = new HashMap<String, Step>();
         for (Step step : steps) {
             jobSteps.put(step.getName(), step);
         }
-        this.map.put(jobName, jobSteps);
+        final Object previousValue = map.putIfAbsent(jobName, jobSteps);
+        if (previousValue != null) {
+            throw new DuplicateJobException("A job configuration with this name [" + jobName
+                    + "] was already registered");
+        }
     }
 
     public void unregisterStepsFromJob(String jobName) {
diff --git a/spring-batch-core/src/test/java/org/springframework/batch/core/configuration/support/MapStepRegistryTests.java b/spring-batch-core/src/test/java/org/springframework/batch/core/configuration/support/MapStepRegistryTests.java
index 146143986..fefa1a3da 100644
--- a/spring-batch-core/src/test/java/org/springframework/batch/core/configuration/support/MapStepRegistryTests.java
+++ b/spring-batch-core/src/test/java/org/springframework/batch/core/configuration/support/MapStepRegistryTests.java
@@ -3,6 +3,7 @@ package org.springframework.batch.core.configuration.support;
 import org.junit.Assert;
 import org.junit.Test;
 import org.springframework.batch.core.Step;
+import org.springframework.batch.core.configuration.DuplicateJobException;
 import org.springframework.batch.core.configuration.StepRegistry;
 import org.springframework.batch.core.launch.NoSuchJobException;
 import org.springframework.batch.core.step.NoSuchStepException;
@@ -12,6 +13,8 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
 
+import static junit.framework.Assert.fail;
+
 /**
  * @author Sebastien Gerard
  */
@@ -20,14 +23,14 @@ public class MapStepRegistryTests {
     private static final String EXCEPTION_NOT_THROWN_MSG = "An exception should have been thrown";
 
     @Test
-    public void registerStepEmptyCollection() {
+    public void registerStepEmptyCollection() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         launchRegisterGetRegistered(stepRegistry, "myJob", getStepCollection());
     }
 
     @Test
-    public void registerStepNullJobName() {
+    public void registerStepNullJobName() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         try {
@@ -38,7 +41,7 @@ public class MapStepRegistryTests {
     }
 
     @Test
-    public void registerStepNullSteps() {
+    public void registerStepNullSteps() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         try {
@@ -49,7 +52,7 @@ public class MapStepRegistryTests {
     }
 
     @Test
-    public void registerStepGetStep() {
+    public void registerStepGetStep() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         launchRegisterGetRegistered(stepRegistry, "myJob",
@@ -61,7 +64,7 @@ public class MapStepRegistryTests {
     }
 
     @Test
-    public void getJobNotRegistered() {
+    public void getJobNotRegistered() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         final String aStepName = "myStep";
@@ -83,7 +86,7 @@ public class MapStepRegistryTests {
     }
 
     @Test
-    public void getStepNotRegistered() {
+    public void getStepNotRegistered() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         final String jobName = "myJob";
@@ -98,7 +101,7 @@ public class MapStepRegistryTests {
     }
 
     @Test
-    public void registerRegisterAgainAndGet() {
+    public void registerTwice() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         final String jobName = "myJob";
@@ -111,14 +114,16 @@ public class MapStepRegistryTests {
         // first registration
         launchRegisterGetRegistered(stepRegistry, jobName, stepsFirstRegistration);
 
-        // register again the job
-        launchRegisterGetRegistered(stepRegistry, jobName,
-                getStepCollection(
-                        createStep("myFourthStep"),
-                        createStep("lastOne")
-                ));
 
-        assertStepsNotRegistered(stepRegistry, jobName, stepsFirstRegistration);
+        // Second registration with same name should fail
+        try {
+            stepRegistry.register(jobName, getStepCollection(
+                    createStep("myFourthStep"),
+                    createStep("lastOne")));
+            fail("Should have failed with a "+DuplicateJobException.class.getSimpleName());
+        } catch (DuplicateJobException e) {
+            // OK
+        }
     }
 
     @Test
@@ -133,7 +138,7 @@ public class MapStepRegistryTests {
     }
 
     @Test
-    public void getStepNullStepName() throws NoSuchJobException {
+    public void getStepNullStepName() throws NoSuchJobException, DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         final String stepName = "myStep";
@@ -147,7 +152,7 @@ public class MapStepRegistryTests {
     }
 
     @Test
-    public void registerStepUnregisterJob() {
+    public void registerStepUnregisterJob() throws DuplicateJobException {
         final StepRegistry stepRegistry = createRegistry();
 
         final Collection<Step> steps = getStepCollection(
@@ -193,7 +198,8 @@ public class MapStepRegistryTests {
         return Arrays.asList(steps);
     }
 
-    protected void launchRegisterGetRegistered(StepRegistry stepRegistry, String jobName, Collection<Step> steps) {
+    protected void launchRegisterGetRegistered(StepRegistry stepRegistry, String jobName, Collection<Step> steps)
+            throws DuplicateJobException {
         stepRegistry.register(jobName, steps);
         assertStepsRegistered(stepRegistry, jobName, steps);
     }