My nautica shirt size is 15.5 ,which size should i choise for polo shirt "small" or "medium"? Thx

You should choose medium. 15.5 is considered a size medium, in all types of shirts. I managed and sold at a Men's Clothing Store.

is the color true burgundy ?

I don't know a lot about men's clothes, but I bought this for my boyfriend--his favorite color is burgundy, and he loves it. The color is a beautiful shade of burgundy, in my opinion.

Hi, I would to know which size of shirt is the right for me, chest 36.5 in, Waist 33 in.

I really can't answer this question, but, there's a Nautica Men's Shirts size chart you can click on: SMALL: Neck 14 - 14 1/2, Chest 35 - 37, Waist 29 - 31 MEDIUM: Neck 15 - 15 1/2, , Chest 38 - 40 Waist 32 - 34 I would choose the size based on your measurements and how you want the shirt to fit - more form fitting or more relaxed. My son likes more form fitting which, for you, would probably be the Small size. Measure your neck......that may help you decide between S and M. What size polo do you normally wear? I think the fit on this is the same as most polos.