Abstract: Phytase action improves mineral bioavailability by lowering the phytic acid level in legumes and oilseeds. Crude phytases from African oil bean seed (Pentaclethra macrophylla), locust bean seed (Parkia biglobosa) and conophor nut (Tetracarpidium conophorum) were isolated and assayed via estimation of inorganic orthophosphate liberated by the hydrolysis of phytic acid. The phytase activities and corresponding protein concentrations for the three under-exploited oilseeds were: 0.720 FmL and 16.85 mgmL for P. macrophylla; 0.078 FmL and 10.65 mgmL for T. conophorFm; and 0.082 FmL and 14.00 FmL for P. biglobosa; respectively. This implies that the Pentaclethra seed phytase has comparatively higher activity with higher protein concentration in the enzyme molecule, followed by the Parkia seed phytase andlastly the Tetracarpidium seed phytase. The optimum temperatures for the phytase activity were 50?C for oil bean and conophor seeds and 60?C for locust bean seed. The optimum pH was 5.0 for oil bean phytase, 4.0 for conophor nut phytase and7.0 for locust bean phytase, respectively. The results show that locust bean phytase was more thermoactive with an alkaline pH optimum conophor nut and oil bean seeds both have acid phytases in their cotyledons.