The toxicity of the molluscicidal plant Ambrosia maritima L. was evaluated against Anopheles stephensi and Aedes aegypti. In the larvicidal assays a negligible mortality was observed in both species after application of the dried leaves in the water at concentrations up to 2000 mg/l. When the powdered leaves were applied at the surface of the water, however, up to 38% of the larvae of A. stephensi were killed at 2000 mg/l. Virtually no inhibitory effect on the larval growth of both species was noticed. It can be concluded that Ambrosia maritima has little or no effect on the larvae of A. stephensi or Ae. aegypti.