Not really slim fit. The chest is a standard size, the shirt balloons out near the bottom like to cover a gut. The length is too short. The sleeves are loose and not slim fit.6' 155# 40" chest slim/muscular build. I like snug fitting clothing so I size down a lot. I got a small (so that explains the length issue) but for a small to fit baggy on me everywhere else is simply a poor "slim fit" cut.