Abstract Globally threatened Sarus cranes Grus antigon are resident at Keoladeo National Park World Heritage site and the surrounding area near Bharatpur, Western Rajasthan, India. In winter, they are joined by c. 200 wintering common cranes Grus grus. On 23 November 2000, 15 Sarus cranes and three common cranes were found dead in a field adjacent to the park, where wheat seed had been sown the previous day. Chemical analyses of seed samples from the field and the cranes’ alimentary tract contents identified residues of the organophosphate insecticide monocrotophos. Monocrotophos concentrations of 0.8 and 1.8 ppm were found in wheat samples, and 0.2–0.74 ppm ( x=0.33) in the alimentary tract contents of five of the seven cranes examined. No other organophosphate or organochlorine pesticides were detected. We conclude that the cranes died from monocrotophos poisoning after eating treated seed. We discuss similar incidents of avian mortality, and recommend that measures be taken to reduce these.