I am 5'4'' and weigh about 150 pounds.  I normally wear a 6 or 8 and in general sizes, a medium.  I got this in a medium.  It is a bit roomy but hangs well.  The legs are a little long by about 2 inches (not washed yet) and the cuffs go to my knuckles when my arms are down.  Neither of these details bothesr me one bit.  The fabric is so soft, the drape is elegant, and the cut and detailing make the set look quite smart.  ( Have the green polka dots on black).  I am wearing these in the hospital and during a recovery time and this is exactly what I had been wishing for. ( Might pin up the cuffs so they down't drag on the hospital floor!)