Please use the following guidelines along with a fabric tape measure to be certain you are ordering the right size. When taking your measurement, wear little or no clothing.

Waist
Measure around your natural waistline, keeping the tape comfortably loose.

Hips
Stand with your heels together, and measure around the fullest part of your hips.

Chest
Wrap the tape around the highest part of your chest and shoulder blades, then drop your arms to your sides to measure.

Neck
Measure around the middle of neck (at the Adam's apple). Allow room for your index finger to fit between the tape and your neck for a comfortable fit.

Inseam
With the appropriate shoes on, measure from your crotch to your desired pant length
 

This is copy of the size chart found at the Polo Ralph Lauren website. You can find it by clicking on this link and then viewing any shirt. Once the shirt is on screen, next to the size selection drop menu, you will find the view size chart link.