diff --git a/debug/org.eclipse.cdt.debug.mi.core/mi/org/eclipse/cdt/debug/mi/core/command/factories/macos/MacOSMIEnvironmentCD.java b/debug/org.eclipse.cdt.debug.mi.core/mi/org/eclipse/cdt/debug/mi/core/command/factories/macos/MacOSMIEnvironmentCD.java
index b9905acb40b..36c1ff61a3e 100644
--- a/debug/org.eclipse.cdt.debug.mi.core/mi/org/eclipse/cdt/debug/mi/core/command/factories/macos/MacOSMIEnvironmentCD.java
+++ b/debug/org.eclipse.cdt.debug.mi.core/mi/org/eclipse/cdt/debug/mi/core/command/factories/macos/MacOSMIEnvironmentCD.java
@@ -1,5 +1,5 @@
 /**********************************************************************
- * Copyright (c) 2006 Nokia and others.
+ * Copyright (c) 2006, 2010 Nokia and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,7 @@
  * 
  * Contributors: 
  * Nokia - Initial API and implementation
+ * Marc-Andre Laperle - fix for bug 263689 (spaces in directory)
 ***********************************************************************/
 package org.eclipse.cdt.debug.mi.core.command.factories.macos;
 
@@ -16,13 +17,15 @@ public class MacOSMIEnvironmentCD extends MIEnvironmentCD {
 
 	public MacOSMIEnvironmentCD(String miVersion, String path) {
 		super(miVersion, path);
-		this.setOperation("cd");//$NON-NLS-1$
+		this.setOperation("-environment-cd");//$NON-NLS-1$
 	}
 	
 	protected String parametersToString() {
 		String[] parameters = getParameters();
 		if (parameters != null && parameters.length == 1) {
-			return '"' + parameters[0] + '"';
+			// To handle spaces in the path, the command string has this format:
+			// -environment-cd "\"/path with spaces\""
+			return "\"\\\"" + parameters[0] + "\\\"\""; //$NON-NLS-1$ //$NON-NLS-2$
 		}
 		return super.parametersToString();		
 	}