The total P contents of 68 soils representing the major agricultural soils of SE Nigeria were fractionated into Al, Fe, Ca and organic and residual phosphates, and the fractions were correlated with yield percentage of maize (Zea mays) and with available P as determined by 2 chemical methods. Total P content varied between 51 ppm P and 2646 ppm P. Organic P accounted for between 30-78.8% of the extractable P, followed by iron phosphate, aluminum phosphate and calcium phosphate in decreasing order of abundance. The bulk of the soil inorganic P was in the residual form, except in the extremely sandy soils with low iron oxide content. Percentage yield of maize correlated positively with aluminum phosphate (r = correlation coefficient = 0.562), iron phosphate (r = 0.546), calcium phosphate (r = 0.491) and organic phosphates (r = 0.455), the correlation coefficient in each case being significant at the 0.1% level, suggesting that all 4 forms contributed to the available P of the maize crop. Aluminum phosphate correlated positively and very highly significantly with resin-extractable P (r = 0.786) and with dilute acid/fluoride-extractable P (r = 0.903), suggesting that the bulk of the available P so determined was aluminum phosphate. Iron phosphate contributed to the extracted available P but calcium and organic phosphates were relatively unimportant.