contrary to a lot of previous reviews, i think this shoe actually runs true to size.  i am a 6 in most shoes, and sometimes a 5.5, and the 6 in this shoe fits like a glove.  it is just a little tight around the elastic edge, which might just require breaking in.  this makes the back dig into my heel a little but can be easily fixed with a couple of heel pads, and then they are super comfy and ready to go anywhere!