The distribution of the ichneumonid Diadegma sp., a parasitoid of Heliothis virescens, was studied in Cuba. Samples were taken from tobacco growing regions in 6 provinces and covering 3 crop sowing dates, between 1979 and 1985. Diadegnw sp. was present in the western and central provinces of Finar del Rio, La Habana and Villa Clara, but was absent from the eastern provinces of Holguin and Granma. In all cases, Diadegma sp. occurred between 4 and 6 weeks after the establishment of H. iirescens in the crop. Recommendations are made for investigations into the effectiveness of mass liberations of Diadegma sp. earlier in thecrop cycle. none