Abstract: Reduction of acidity level is of immense importance in sustaining productivity of majority of tropical soils; yet liming raises production cost besides the possibility of environmental contamination. In evaluating the lime effectiveness of some organic, organo-mineral and inorganic phosphorus (P) fertilizers, investigations were conducted to determine changes in pH and P availability in a Typic Paleustalf incubated with P fertilizers at various periods (7, 14 and 21 days) relative to conventional lime application. Each treatment was thoroughly mixed with 50 g soil and moistened to 60% field capacity with distilled water. Only lime was used in the first experiment while the second involved 15 sole and combined applications of lime (2 t ha-1) and P (88 kg P ha-1); the P fertilizer sources being Crystalliser, CRYS (a blend of Sokoto rock phosphate, SRP and talc), Single Super Phosphate (SSP) and Organic Fertilizer (OF) in addition to control. Treatments were replicated three times in Completely Randomised Design (CRD). Liming at 2.0 t ha-1 was optimum, soil pH being 6.1-6.6. Soil amendment increased pH to between 5.5 and 7.5 compared with the average of 5.2 for the control. At the end of a 3-week incubation period, untreated soil remained acidic (pH = 4.8) while reductions in acidity (pH 5.2-7.4) were recorded for the amended samples. Liming at 2 t ha-1 also resulted in maximum P-release of 17.33, 16.76 and 15.09 mg P kg-1 after 1, 2 and 3 weeks of incubation, respectively while the untreated soils had the least available P at all incubation periods. Lime (applied alone) and lime + P treatments gave the highest soil pH values of 7.0-7.2 after 7 days of incubation. Soil pH decreased gradually with incubation periods in all treatments with control becoming more acidic. Sole and combined applications of the P sources led to higher pH values of 5.5 for organic fertilizer (O.F), rock phosphate, CRYS (5.0) and single super phosphate; SSP (5.0), while CRYS + SSP, CRYS + OF and OF + SSP gave 5.8, 5.6 and 5.7, respectively compared with control (5.2). Relative Agronomic Efficiency (RAE)/Lime Effectiveness (LE) based on soil pH was indicative of the ameliorating ability of OF while higher amount of CRYS would be required to reduce soil acidity. Liming and fertilizer application increased soil pH and enhanced P release, respectively. The application of OF and CRYS could prove multipurpose (by its lime effectiveness and P releasing property) especially to farmers in developing countries challenged by acid soils and limited by high cost of soil management.