diff --git a/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn b/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn
index 6b0103e7b423e9972c6ff3a2b9a96e300572a6f3..8b486e3284e7c001fa7f826d520ee3eaf1e88543 100755
--- a/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn
+++ b/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn
@@ -168,6 +168,23 @@ type class OuterClass {
 	}
 }
 
+// constant initialization
+type class ConstantInitialization1 {
+	const integer const_int; 
+	
+	function f_create(integer pl_create_int) {
+		const_int := pl_create_int;
+	}
+}
+
+type class ConstantInitialization2 {
+	const integer const_int := 0; 
+	
+	create(integer pl_create_int) {
+		const_int := pl_create_int;
+	}
+}
+
 type class ReuseClass {
 	var charstring vl_orig := "abc";
 	
diff --git a/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn b/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn
index c8b1cd0988777034e6abc52b2d7e190d6bd1f125..6cbbacdbdf4a034fa21399357e98b4f7403c7385 100644
--- a/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn
+++ b/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn
@@ -136,6 +136,14 @@ type class ConstructorOverrideSub {
 	}
 }
 
+type class ConstantInitialization {
+	const integer const_int; 
+	
+	create(integer pl_create_int) {
+		const_int := pl_create_int;
+	}
+}
+
 // runs on compatibility
 type class RunsonClass1 runs on CT { }
 type class RunsonClass2 extends RunsonClass1 runs on CT { }
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Assignment_Statement.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Assignment_Statement.java
index 881c2d227960bbd6723cb67175f84dd331705f78..55d7314429b9b5eecc792efe83563def00431893 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Assignment_Statement.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Assignment_Statement.java
@@ -74,6 +74,9 @@ public final class Assignment_Statement extends Statement {
 	private static final String OMITTOMANDATORYASSIGNMENT1 = "Omit value can only be assigned to an optional field of a record or set value";
 	private static final String OMITTOMANDATORYASSIGNMENT2 = "Assignment of `omit'' to mandatory field `{0}'' of type `{1}''";
 	private static final String STATEMENT_NAME = "assignment";
+	
+	private static final String VALUEALREADYSET = "{0} value can only be assigned once";
+	private static final String BADCONSTANTASSIGNMENT = "Constant can only be initialized in a constructor";
 
 	private final Reference reference;
 	private final TTCN3Template template;
@@ -235,12 +238,40 @@ public final class Assignment_Statement extends Statement {
 			((Def_Var_Template) assignment).setWritten();
 			checkTemplateAssignment(timestamp, assignment,Expected_Value_type.EXPECTED_TEMPLATE,null);
 			break;
+		case A_CONST:
+			final IValue temporalConstValue = template.getValue();
+			if (temporalConstValue != null) {
+				checkConstAssignment(timestamp, assignment, temporalConstValue);
+				template.setMyGovernor(temporalConstValue.getMyGovernor());
+				break;
+			}
+			break;
 		default:
 			reference.getLocation().reportSemanticError(MessageFormat.format(VARIABLEREFERENCEEXPECTED, assignment.getAssignmentName()));
 			reference.setIsErroneous(true);
 			isErroneous = true;
 		}
 	}
+	
+	private void checkConstAssignment(final CompilationTimeStamp timestamp, final Assignment assignment, final IValue value) {
+		Def_Const def = (Def_Const)assignment;
+		if (def.getValue() != null) {
+			value.getLocation().reportSemanticError(
+				MessageFormat.format(VALUEALREADYSET, "Constant"));
+		}
+		final Scope scope = value.getMyScope();
+		if (scope instanceof StatementBlock) {
+			Definition definition = ((StatementBlock)scope).getMyDefinition();
+			if (definition instanceof Def_Function) {
+				final Identifier id = ((Def_Function)definition).getIdentifier();
+				if (id.getName().equals("create")) {
+					return;
+				}
+			}
+		}
+		value.getLocation().reportSemanticError(BADCONSTANTASSIGNMENT);
+	}
+
 
 	private void checkVarAssignment(final CompilationTimeStamp timestamp, final Assignment assignment, final IValue value) {
 		final IType varType = getType(timestamp, assignment);
diff --git a/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java b/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java
index dc53c78b67f8383e9718d65ea8d162971cab53c8..b584aecd113a6263c1808694dc34ba0846492a89 100755
--- a/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java
+++ b/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java
@@ -152,7 +152,7 @@ public class OOP_Semantic_tests {
 	
 	private ArrayList<MarkerToCheck> oopNegative_ttcn_initializer() {
 		//oopNegativeSemanticTest.ttcn
-		ArrayList<MarkerToCheck> markersToCheck = new ArrayList<MarkerToCheck>(77);
+		ArrayList<MarkerToCheck> markersToCheck = new ArrayList<MarkerToCheck>(79);
 		int lineNum = 32;
 		markersToCheck.add(new MarkerToCheck("class type expected",  lineNum, IMarker.SEVERITY_ERROR));
 		lineNum += 10;
@@ -219,7 +219,11 @@ public class OOP_Semantic_tests {
 			markersToCheck.add(new MarkerToCheck("Class field visibility must be private or protected", lineNum++, IMarker.SEVERITY_ERROR));
 		}
 		markersToCheck.add(new MarkerToCheck("Class field visibility must be private or protected",  ++lineNum, IMarker.SEVERITY_ERROR));
-		lineNum += 16;
+		lineNum += 15;
+		markersToCheck.add(new MarkerToCheck("Constant can only be initialized in a constructor",  lineNum, IMarker.SEVERITY_ERROR));
+		lineNum += 8;
+		markersToCheck.add(new MarkerToCheck("Constant value can only be assigned once",  lineNum, IMarker.SEVERITY_ERROR));
+		lineNum += 10;
 		markersToCheck.add(new MarkerToCheck("integer value was expected",  lineNum, IMarker.SEVERITY_ERROR));
 		lineNum += 4;
 		markersToCheck.add(new MarkerToCheck("Constant must be initialized",  lineNum, IMarker.SEVERITY_ERROR));