Tanzania Journal of Agricultural Sciences 2003, Vol. 6(1) : 39-44A glasshouse pot experiment was carrriedout at SUA farm, Morogoro. Tanzania to investigate the effect of Minjingu phosphate rock (MPR) and farmyard manure (FYM) applied to an Oxic Haplustults on Bray I-P and the response of maize (Zea mays (L.) variety staha) to the applied MPR and FYM in a 4 factorial experiment in a completely randomized block design. MPR was applied at the rates of 0.50. 100 and 150mg P kg-1 soil and FYM at the rates of 0.7, 5.15 and 30g kg-1 soil. The MPR and FYMwe re thoroughly mixed with 4.5 kg of 4mm sieved soil sample portions- in 5-litre capacity plastic pots and incubated at 75% field capacity moisture content for 28 days before sowing four maize seeds and thinned t0 two plants one week after germination. The whole plant portions above the soil level in the pots were harvested at the age of 6 weeks for dry matter yields and P content determinations. The highest MPR and FYM combination increased the amounts of Bray - 1-P by 268% and maize dry matter yields by 91%. compared to the control. The above increases were attributed to the dissolution of the MPR and the decomposition and mineralization of the FYM hence releasing P and reducing the P-retentibn capacity of the soil and improvement soil physical, chemical and biological soil conditions by the applied FYM.