These are slightly heavier material than the 3-packs I have usually bought, i.e. W--Mart. I have had them since Jan '13 (three months now) and they have been washed multiple times.  They have retained shape VERY well, unlike the typical T-shirts which are out-of-shape after two or three washes. These were poly/cotton blend.  More info: in Feb '13 I purchased 4 more - same T-shirt, but 100% cotton.  They too have "passed the test" of multiple laundry cycles.