diff --git a/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_Global.cs b/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_Global.cs
index 8a2a77c076..d84f49c224 100644
--- a/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_Global.cs
+++ b/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_Global.cs
@@ -161,6 +161,9 @@ namespace ICSharpCode.NRefactory.CSharp
 				default:
 					throw new InvalidOperationException("unsupported class type : " + typeDeclaration.ClassType);
 			}
+			
+			foreach (var constraint in typeDeclaration.Constraints)
+				constraint.AcceptVisitor (this);
 
 			FixOpenBrace(braceStyle, typeDeclaration.LBraceToken);
 
@@ -248,5 +251,20 @@ namespace ICSharpCode.NRefactory.CSharp
 			if (comment.StartsLine && !HadErrors && (!policy.KeepCommentsAtFirstColumn || comment.StartLocation.Column > 1))
 				FixIndentation(comment);
 		}
+
+		public override void VisitConstraint(Constraint constraint)
+		{
+			VisitChildrenToFormat (constraint, node => {
+				if (node is AstType) {
+					node.AcceptVisitor (this);
+				} else if (node.Role == Roles.LPar) {
+					ForceSpacesBefore (node, false);
+					ForceSpacesAfter (node, false);
+				} else if (node.Role ==Roles.Comma) {
+					ForceSpacesBefore (node, false);
+					ForceSpacesAfter (node, true);
+				}
+			});
+		}
 	}
 }
\ No newline at end of file
diff --git a/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_TypeMembers.cs b/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_TypeMembers.cs
index d3abd82f9e..415450457e 100644
--- a/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_TypeMembers.cs
+++ b/ICSharpCode.NRefactory.CSharp/Formatter/FormattingVisitor_TypeMembers.cs
@@ -347,6 +347,9 @@ namespace ICSharpCode.NRefactory.CSharp
 				ForceSpacesAfter(methodDeclaration.LParToken, policy.SpaceBetweenEmptyMethodDeclarationParentheses);
 				ForceSpacesBefore(methodDeclaration.RParToken, policy.SpaceBetweenEmptyMethodDeclarationParentheses);
 			}
+			
+			foreach (var constraint in methodDeclaration.Constraints)
+				constraint.AcceptVisitor (this);
 
 			if (!methodDeclaration.Body.IsNull) {
 				FixOpenBrace(policy.MethodBraceStyle, methodDeclaration.Body.LBraceToken);
diff --git a/ICSharpCode.NRefactory.CSharp/Parser/CSharpParser.cs b/ICSharpCode.NRefactory.CSharp/Parser/CSharpParser.cs
index 5eff5f6c4f..59b829a154 100644
--- a/ICSharpCode.NRefactory.CSharp/Parser/CSharpParser.cs
+++ b/ICSharpCode.NRefactory.CSharp/Parser/CSharpParser.cs
@@ -261,9 +261,9 @@ namespace ICSharpCode.NRefactory.CSharp
 					switch (sce.Constraint) {
 						case SpecialConstraint.Class:
 							return new PrimitiveType ("class", Convert (sce.Location));
-						case SpecialConstraint.Struct:
+							case SpecialConstraint.Struct:
 							return new PrimitiveType ("struct", Convert (sce.Location));
-						case SpecialConstraint.Constructor:
+							case SpecialConstraint.Constructor:
 							return new PrimitiveType ("new", Convert (sce.Location));
 					}
 				}
@@ -2651,6 +2651,23 @@ namespace ICSharpCode.NRefactory.CSharp
 					if (c.ConstraintExpressions != null) {
 						foreach (var expr in c.ConstraintExpressions) {
 							constraint.AddChild (ConvertToType (expr), Roles.BaseType);
+							if (expr is SpecialContraintExpr) {
+								var sce = (SpecialContraintExpr)expr;
+								switch (sce.Constraint) {
+									case SpecialConstraint.Class:
+										break;
+									case SpecialConstraint.Struct:
+										break;
+									case SpecialConstraint.Constructor:
+										var bl = LocationsBag.GetLocations (expr);
+										if (bl != null) {
+											constraint.AddChild (new CSharpTokenNode (Convert (bl[0]), Roles.LPar), Roles.LPar);
+											constraint.AddChild (new CSharpTokenNode (Convert (bl[1]), Roles.RPar), Roles.RPar);
+										}
+										break;
+								}
+							}
+
 							if (commaLocs != null && curComma < commaLocs.Count)
 								constraint.AddChild (new CSharpTokenNode (Convert (commaLocs [curComma++]), Roles.Comma), Roles.Comma);
 						}
diff --git a/ICSharpCode.NRefactory.Tests/FormattingTests/TestFormattingBugs.cs b/ICSharpCode.NRefactory.Tests/FormattingTests/TestFormattingBugs.cs
index 5ff03ee8ba..1689f20a46 100644
--- a/ICSharpCode.NRefactory.Tests/FormattingTests/TestFormattingBugs.cs
+++ b/ICSharpCode.NRefactory.Tests/FormattingTests/TestFormattingBugs.cs
@@ -350,6 +350,32 @@ foo ();
 	}
 }");
 		}
+	
+
+		/// <summary>
+		/// Bug 12270 - Code formatter breaks new() constraints
+		/// </summary>
+		[Test]
+		public void TestBug12270()
+		{
+			CSharpFormattingOptions policy = FormattingOptionsFactory.CreateMono();
+
+			Test(policy,
+@"class C
+{
+	public void Test<T> () where T : new  ()
+	{
+	}
+}",
+@"class C
+{
+	public void Test<T> () where T : new()
+	{
+	}
+}");
+		}
+
+
 	}
 }