A single locking cotton feeder was designed to maintain a constant feed rate of individual pods at the ginning point of the double roller (DR) cotton gin. It consists of a pair of feed rollers, spike cylinders, grids, feed hoppers and distribution chutes. The spike cylinder has spikes, the tips of which are closer to the supply roller than the fixed thickness of cotton and have a ginning interval. The spike cylinder travels at a linear speed greater than the feed roller, whereby the cotton pods held between the feed rollers are hit by the spikes of the spike cylinder, thus ensuring a single locking of the cotton. The effect of single locking on the ginning efficiency of the DR cotton gin was investigated. The degree of unlocking was determined by measuring the change in cotton bulk density before and after passing through the feeder, which decreases with increasing spike cylinder speed. It was found that the DR cotton gin output was increased by 15 to 20% by adopting a single locking compared to the conventional feeding system consisting of an auto feeder and a micro feeder. Cotton quality was also found to improve in color grade. A single locking feeder has proved to be very useful in the cotton gin industry in India.