Pooled samples of tobacco hornworms collected from a field sprayed with 0.84 kg/ha of diazinon were analyzed for residues at various intervals after application. No residues of the toxic metabolite diazoxon were detected (sensitivity 0.5 ppm) in any sample. Only one sample exceeded 1.0 ppm of the parent compound and was collected 4 hours after spraying. Residues declined over time (P<0.01) and none were detected (sensitivity 0.1 ppm) 18 days after spraying. the potential hazard to birds eating these insects appeared to be minimal.