AbstractA study was carried out to investigate the organisms associated with the spoilage of yam chips and flour in many locations in 5 states of Nigeria. Monilinia fructicola, Aspergillus flavus, A. fumigatus, A. niger, Penicillium expansum, P. wortmanni, P. duponti, P. funiculosum, Rhizopus sexualis, Piricularia sp., Cladosporium cucumerinum, Helminthosporium sp. and Mucor sp. were isolated and found to cause spoilage of the yam products. Araecerus fasciculatus, Tribolium castaneum and Ahasverus advena were found on the yam chips as infesting insects. The yam chips or flour were either contained in exposed baskets or sealed in fibre bags in the market stalls. A. fumigatus had the highest occurrence. Most of the fungi were found not to sporulate heavily at a temperature of 10–15 °C while only spores of A. fumigatus, A. flavus and C. cucumerinum germinated at 32.5% relative humidity.