I am 5'7" 140 lbs and the extra small fit. The pants are cut a bit weird, almost like for a man, and the tag is on the side so I had to cut it off as it rubbed my hip bone. The shirt is very boxy, but for $15 you get what you pay for.

Update - after wearing these a few times the weird cut on the pants was driving me nuts. I kept tugging and adjusting my pants all day at work. Finally I have up. These scrubs claim to be women's but they are more of a unisex cut. I ended up buying Dickies scrub set for women, also available on Amazon, and was so pleased I now own 4 sets. They cost almost twice as much as these, but they are cut for women and are a much better quality. I did not throw these away, I now use them when I paint sets for my kids school plays. If you have a job where you need well made sturdy scrubs that fit them buy the Dickies, if you are buying scrubs to paint your house then these will work fine.