For all the talk about fit, I ordered both the small and medium in order to cover the possibility of fit problems. I am 5'2" tall 140lbs and have a 29.5-30" waist with both jeans and khaki pants. The small pant fit me almost perfectly aside from being 1.5" long in the legs (story of my life), otherwise I would say they are perfect in size for my height and waist size. Having a 29.5" waist line these pants in a small have about 1 more inch of stretch in the waist line but I would say my 29.5" waist is about max for the Small. So if your  waist is larger than a 30" I would order a medium for sure. If your taller than 5'4" I would order a medium as well. The pants are light and look to be of decent quality (only time will tell). The zippers are the one thing that worry me but I have said that before about a product and been pleasantly surprised. Once again only time will tell. Overall I am pleasantly surprise. If these pants hold up through the spring and summer hiking season here in the northwest I would give them 5 starts for best bang for buck as I only paid $19 with prime for them. As an everyday kick around pant I would say they would be a 5 star for the price. I myself will actually use them for hiking, camping and outdoor activities so quality will be tested.