I really like this rug, I bought the hallway runner.  However, I recall reading in the description that there was a non-slip backing of some sort attached to the rug, so that a rug pad wouldn't be required on wood floors.  The underside of this rug doesn't appear to be lined with anything.  I am fairly new to rugs though, so maybe I'm just misinformed, not sure.  Pretty rug though and very soft and comfortable.