diff --git a/src/main/java/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiator.java b/src/main/java/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiator.java
index 05b7d5cd3..9b35c17e1 100644
--- a/src/main/java/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiator.java
+++ b/src/main/java/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiator.java
@@ -229,15 +229,19 @@ public class KotlinClassGeneratingEntityInstantiator extends ClassGeneratingEnti
 				int slot = i / 32;
 				int offset = slot * 32;
 
-				Object param = provider.getParameterValue(parameters.get(i));
+				Parameter<Object, P> parameter = parameters.get(i);
+				Class<Object> type = parameter.getType().getType();
+				Object param = provider.getParameterValue(parameter);
 
 				KParameter kParameter = kParameters.get(i);
 
 				// what about null and parameter is mandatory? What if parameter is non-null?
-				if (kParameter.isOptional()) {
+				if (kParameter.isOptional() && param == null) {
 
-					if (param == null) {
-						defaulting[slot] = defaulting[slot] | (1 << (i - offset));
+					defaulting[slot] = defaulting[slot] | (1 << (i - offset));
+
+					if (type.isPrimitive()) {
+						param = getPrimitiveDefault(type);
 					}
 				}
 
@@ -251,5 +255,42 @@ public class KotlinClassGeneratingEntityInstantiator extends ClassGeneratingEnti
 
 			return params;
 		}
+
+		private static Object getPrimitiveDefault(Class<?> type) {
+
+			if (type == Byte.TYPE || type == Byte.class) {
+				return (byte) 0;
+			}
+
+			if (type == Short.TYPE || type == Short.class) {
+				return (short) 0;
+			}
+
+			if (type == Integer.TYPE || type == Integer.class) {
+				return 0;
+			}
+
+			if (type == Long.TYPE || type == Long.class) {
+				return 0L;
+			}
+
+			if (type == Float.TYPE || type == Float.class) {
+				return 0F;
+			}
+
+			if (type == Double.TYPE || type == Double.class) {
+				return 0D;
+			}
+
+			if (type == Character.TYPE || type == Character.class) {
+				return '\u0000';
+			}
+
+			if (type == Boolean.TYPE) {
+				return Boolean.FALSE;
+			}
+
+			throw new IllegalArgumentException(String.format("Primitive type %s not supported!", type));
+		}
 	}
 }
diff --git a/src/test/kotlin/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiatorUnitTests.kt b/src/test/kotlin/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiatorUnitTests.kt
index a2d05cb66..14e0da6b4 100644
--- a/src/test/kotlin/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiatorUnitTests.kt
+++ b/src/test/kotlin/org/springframework/data/convert/KotlinClassGeneratingEntityInstantiatorUnitTests.kt
@@ -96,6 +96,27 @@ class KotlinClassGeneratingEntityInstantiatorUnitTests {
 				.hasCauseInstanceOf(IllegalArgumentException::class.java)
 	}
 
+	@Test // DATACMNS-1200
+	fun `should apply primitive defaulting for absent parameters`() {
+
+		val entity = this.entity as PersistentEntity<WithPrimitiveDefaulting, SamplePersistentProperty>
+		val constructor = PreferredConstructorDiscoverer.discover<WithPrimitiveDefaulting, SamplePersistentProperty>(WithPrimitiveDefaulting::class.java)
+
+		doReturn(constructor).whenever(entity).persistenceConstructor
+		doReturn(constructor.constructor.declaringClass).whenever(entity).type
+
+		val instance: WithPrimitiveDefaulting = KotlinClassGeneratingEntityInstantiator().createInstance(entity, provider)
+
+		Assertions.assertThat(instance.aByte).isEqualTo(0)
+		Assertions.assertThat(instance.aShort).isEqualTo(0)
+		Assertions.assertThat(instance.anInt).isEqualTo(0)
+		Assertions.assertThat(instance.aLong).isEqualTo(0L)
+		Assertions.assertThat(instance.aFloat).isEqualTo(0.0f)
+		Assertions.assertThat(instance.aDouble).isEqualTo(0.0)
+		Assertions.assertThat(instance.aChar).isEqualTo('a')
+		Assertions.assertThat(instance.aBool).isTrue()
+	}
+
 	data class Contact(val firstname: String, val lastname: String)
 
 	data class ContactWithDefaulting(val prop0: String, val prop1: String = "White", val prop2: String,
@@ -113,5 +134,8 @@ class KotlinClassGeneratingEntityInstantiatorUnitTests {
 	)
 
 	data class WithBoolean(val state: Boolean)
+
+	data class WithPrimitiveDefaulting(val aByte: Byte = 0, val aShort: Short = 0, val anInt: Int = 0, val aLong: Long = 0L,
+									   val aFloat: Float = 0.0f, val aDouble: Double = 0.0, val aChar: Char = 'a', val aBool: Boolean = true)
 }