diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/scanner/PreprocessorBugsTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/scanner/PreprocessorBugsTests.java
index 86a776868d4..e6ed8b24c7d 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/scanner/PreprocessorBugsTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/scanner/PreprocessorBugsTests.java
@@ -131,4 +131,22 @@ public class PreprocessorBugsTests extends PreprocessorTestsBase {
 		validateEOF();
 		validateProblemCount(2);
 	}
+	
+	// #if true
+	// yes
+	// #else
+	// no
+	// #endif
+	// #if false
+	// no
+	// #else
+	// yes
+	// #endif
+	public void testTrueInConditionalExpression_Bug246369() throws Exception {
+		initializeScanner();
+		validateIdentifier("yes");
+		validateIdentifier("yes");
+		validateEOF();
+		validateProblemCount(0);
+	}
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/ExpressionEvaluator.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/ExpressionEvaluator.java
index 2bd913ee43b..3cf380f0458 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/ExpressionEvaluator.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/parser/scanner/ExpressionEvaluator.java
@@ -238,6 +238,12 @@ class ExpressionEvaluator {
         	long val= getValue(fTokens);
         	consume();
         	return val;
+        case IToken.t_true:
+        	consume();
+        	return 1;
+        case IToken.t_false:
+        	consume();
+        	return 0;
         case CPreprocessor.tDEFINED:
             return handleDefined();
         case IToken.tLPAREN: