We studied the effectiveness of glyphosate [N-(phosphono-methyl)glycine] for the control of Orobanche spp. in the field when applied to the crop foliage prior to the emergence of the parasite. The best Orobanche control in October-sown carrots (Daucus carota L.) parasitized by Orobanche crenata Forsk. and O. aegyptiaca Pers. and in December-sown broad bean (Vicia faba L.) and peas (Pisum sativum L.) parasitized by O. crenata was obtained by spraying twice, 2 weeks apart, in late January and in February, respectively. Carrot root yield remained unaffected by glyphosate at rates up to 200 g/ha. In heavily infested fields, carrots were irreversibly damaged by early Orobanche parasitism. The highest yields of pods of broad beans occurred after two or three applications of 150 g/ha glyphosate. Peas were seriously damaged by 150 g/ha. Two or three sprays of 50 g/ha glyphosate resulted in the highest green-kernel yield of pea where the soil was not heavily infested. Glyphosate effectively reduced O. cernua Loeffl. emergence in non-irrigated tomatoes (Lycopersicum esculentum Mill.), but was very phytotoxic to the crop. Glyphosate was highly effective in controlling Orobanche spp.; however, marginal selectivity may be sufficient in some crops and not in glyphosate-susceptible ones.