I wore mine all winter without socks and they don't smell at all. The more expensive sheep-fleece lined boots, like Uggs or the Celtic sheepskin ones, keep your feet really warm and cosy without getting sweaty and smelly. I'd imagine the cheaper versions with synthetic 'fleece' inside do whiff a bit. I couldn't wear mine now- I get too hot at the best of times and would overheat wearing my Uggs in the sunshine. More cold-blooded (skinny!) people may still need to keep their tootsies toasty.