I love this shirt!  These are form fitted shirts, so they fit very nice.  I ordered a large the first time around and it is a little tight for me in the chest area.  I have a 48" chest and 34" waste.  Since it is form fitting, it really fits me like a glove, but I feel that a larger size would give me more comfort while doing physical activity.  I ordered my second shirt in an XL and it should do the trick.  After receiving these shirts, I know what the appeal is.  They breathe very well, they're stylish and very pratical for the outdoors or wherever you wear this shirt.  I've gotten quite a few compliments.  You can't go wrong with this purchase.