Field trials were conducted in 1988 to evaluate the effectiveness of Steinernema (=Neoaplectana) carpocapsae (Weiser) in controlling the fire ant. Infective juveniles (IJ) of the nematode were applied as drench on 235 and 422 mounds, respectively for 2-month summer and 6-week fall evaluation periods. In comparative trials, amidinohydrazone (Amdro) was applied to 249 (summer) and 65 (fall) active mounds, with 245 (summer) and 78 (fall) untreated active as controls. Nematode treatments resulted in an average of 47% control (Abbott's formula) in summer trials and 19-88% control in the fall trials, compared with 39% and 47% control, respectively with amidinohydrazone. Active mounds treated with nematodes or amidinohydrazone had significantly fewer individuals than control mounds in summer trials.