Cotton fiber properties and their variations within a bale and the effect of blending on those properties were studied. The main focus was on the short fiber content. Two bales of US Upland cotton were selected. Fibers from each bale were blended using various opening and cleaning machines. The effect of blending on the sample uniformity and the property changes were studied. The variation of the short fiber content within a bale was found to be very high which affected accuracy of the test results. The blending significantly reduced the sample nonuniformity. However, the variation of short fiber content was still high even after processing. In fact, processing further beyond the Superior Cleaner did not reduce the sample nonuniformity significantly. Instead, further processing introduced minor fiber breakage, which was manifested by the increase of short fiber content and a slight decrease of fiber length. In addition, the processing introduced more neps.