Size runs a bit small. Most of the button-down or polos I wear for work are a size Large and they fit me well. Reading other reviews I ordered this riding jersey in an XL. It's still snug. It's tighter across the shoulders and chest than any of my standard t-shirts or work shirts. The same is true of the torso. I'm hoping that losing 30lbs will improve the situation so the shirt doesn't show off the fact that I like beer and need to lose 30lbs. To add to this, the neck of the shirt doesn't stretch. It's pretty snug getting it over your head to put it on or take it off. I felt a bit awkward struggling to pull a sweaty shirt off my head at the bike park / trail head a couple days ago. Otherwise I like the jersey. It was definitely breathable during the ride. I could feel the cooling breeze while riding and never felt overheated on an 80F day. If I can lose the weight I'll probably buy more. Get past the fit issues and it's a decent riding jersey.This jersey seems really well-constructed, nice seams, smooth fabric and ventilation. Unfortunately, the fit is too small. I wear a small in other brands (Zoic, Fox), but this jersey didn't work in that size. The neck was too tight and I had to squeeze my head through, plus the shoulders were narrow and pulled tight when my arms were outstretched for riding. Size up when ordering.Not cotton shirt I thought it was