I have worn a woman's size 10 and a half for many, many years. When I bought these shoes I ordered that size. When I got them, even though they said 10 and a half, they were either a 10 or 9 and a half. Way too tight. I spent ten dollars returning them and got an 11. Better, but snug aroun the toes. I will now need to return them for an 11 wide, if they have it. Lest you think that this one style is the only one that runs small, during all this I ordered another pair of asics, because other than the size issue they feel comfortable. I ordered these in an 11, and although they are long enough, they are again tight around the toes. If you do order any asics, they do have nice shoes, order a half size up and make them a size wider than you normally do.