Malathion, an organic phosphate insecticide, has become the agent most commonly used for suicide attempts in Guyana. The clinical characteristics of 264 cases are described. As well with other types of organic phosphate poisoning, atropine is the mainstay of therapy after exposure to the toxin is terminated. The value of oximes in the treatment of malathion poisoning is not clear. The increase in malathion suicides is related to sociocultural factors.