diff --git a/src/context2d.cc b/src/context2d.cc
index e3e7e37..f2bbb80 100644
--- a/src/context2d.cc
+++ b/src/context2d.cc
@@ -262,8 +262,11 @@ Context2d::GetLineWidth(Local<String> prop, const AccessorInfo &info) {
 
 void
 Context2d::SetLineWidth(Local<String> prop, Local<Value> val, const AccessorInfo &info) {
-  Context2d *context = ObjectWrap::Unwrap<Context2d>(info.This());
-  cairo_set_line_width(context->getContext(), val->NumberValue());
+  double n = val->NumberValue();
+  if (n > 0) {
+    Context2d *context = ObjectWrap::Unwrap<Context2d>(info.This());
+    cairo_set_line_width(context->getContext(), n);
+  }
 }
 
 /*
diff --git a/test/canvas.test.js b/test/canvas.test.js
index 346f352..0804507 100644
--- a/test/canvas.test.js
+++ b/test/canvas.test.js
@@ -260,6 +260,12 @@ module.exports = {
     ctx.beginPath();
     ctx.lineWidth = 10.0;
     assert.equal(10, ctx.lineWidth);
+    // ctx.lineWidth = Infinity;
+    assert.equal(10, ctx.lineWidth);
+    ctx.lineWidth = -5;
+    assert.equal(10, ctx.lineWidth);
+    ctx.lineWidth = 0;
+    assert.equal(10, ctx.lineWidth);
     ctx.moveTo(50, 50);
     ctx.lineTo(50, 100);
     ctx.lineTo(80, 120);