Surveys carried out during two seasons showed that the bean fly (BF), Ophiomyia phaseoli (Tyron), is widely distributed in Ethiopia. It was found on haricot bean (Phaseolus vulgaris L.), cowpea (Vigna unguiculata L.) and soybean (Glycine max. (L.) Merr.) but caused economic damage only on haricot bean. The leguminous bush Crotalaria laburnifolia L. was the only wild host plant supporting BF and its parasitoids throughout the year in some parts of Ethiopia. These surveys confirmed that Ophiomyia phaseoli is the only species of bean fly found in this country. Bean fly incidence on the wild host was highest during the dry season, between December and March. Seventeen species of parasitoids were recorded. Of these, the pteromalids Sphegigaster stepicola Bouc. and S. brunneicornis (Ferr.) were the most common species on the wild plant host, accounting for up to 44.5% ( hivin x = 26.2 +- 3.1%; hivin x +- se) of BF parasitism. Parasitism by the braconid Opius phaseoli Fischer was low, ranging from 0% to 23.2% ( hivin x = 5.6 +- 1.3%). However, on haricot bean, it was the major parasitoid, with over 87% of BF parasitism. This fact suggest the possibility that the host plants play an important role in BF dynamics.