Extension demonstrations of starter fertilizer on cotton were applied at 18 Mississippi locations during 1985-87. The starter fertilizer used was 150 lbs. of 10-34-0 or 11-37-0 applied in a 3-4" band on top of the ground behind the planter's press wheel at the time of planting. Positive yield responses were noted in 17 of the 18 locations, with the yield increases being statistically significant or highly significant in 13 locations. In addition to increasing yields, plants treated with starter fertilizer appeared to better withstand early adverse conditions. Plant maps revealed that plants treated with starter fertilizer initiated fruiting I node earlier than untreated plants. In some cases, starter fertilizer treated plants matured earlier than untreated plants, and in other cases, no difference in maturity was noted.