Participatory Rural Appraisal (PRA) exercises conducted in Nyamonyo and Nyatieko villages south west Kenya, indicated that farmers were getting low crop yields mainly due to low soil fertility. A trial was therefore initiated in order to determine the effect of organic and inorganic fertilisers on maize grain yield. Five treatments were tested in a randomised complete block design replicated on 8 farmers' fields. The treatments were: 1) 10 t ha-I compost/farm yard manure(FYM) , 2) 15 kg N ha.l + 15 kg PzOs, ha-l + 10 t ha.1 Compost/FYM, 3) 30 kg N ha-I+ 30 kg PzOs ha.1 + 10 t ha-I Compost/FYM, 4) 60 kg N ha-l + 60 kg PzOs ha-I (research recommended rate) and 5) 75 kg N ha.l + 50 kg PzOs ha-I (FURP recommended rate). At Nyamonyo site application of 60 kg N ha.1 + 60 kg PzO ha.l gave the highest mean yield followed by application of 75 kg N ha-I + 50 kg PzOsha-l. At Nyatieko site, 75 kg N ha -I + 50 kg PzOsha -I gave the highest mean yield (2430 kg ha-I) followed by 30 kg N ha -I + 30 kg PzOs ha -I + 10 t ha.l compost/FYM. Use of 10 t ha-l compost/FYM alone resulted in the lowest yield.