SummaryActivity at the hive entrance, hive occupancy and worker survival were monitored in two spraying operations involving 10 spray cycles and application rates of 10–41 g active ingredient ha−1. Applications of 15–41 g ha−1caused hyperactivity and some colonies probably deserted their hives. Sprays of 10–24 g ha−1had no immediate effect on survival, but mortality increased after sprays of 28–41 g ha−1. Foraging by workers before sunrise, when spraying ended, and the greater toxicity of endosulfan at high temperatures, may have increased the hazard of endosulfan drift sprays to honeybees in Somalia.