Two field experiments were carried out during two successive seasons of 1998 and 1999 at the experimental station of National Research Centre in Shalakan , to study the response of cowpea plant to chemical and bio phosphorus fertilizers . Each experiment included 3 rates of chemical phosphorus fertilizer , i.e. 0 , 150 and 300 kg/fed.as super phosphate , and 3 rates of phosphorine (bio-phosphorus) , i.e. 0, , 14 and 21 g/kg of seeds . The important obtained results are shown as follows : The addition rate of phosphorus up to 300 kg/fed. as super-phosphate per feddan had a gradual increase in values of length of  plant , average number of leaves and shoots as well as fresh and dry weight of whole plant and its different organs. Treating seeds of cowpea before sowing by phosphorine at rate of 14 g/kg and/or 21 g/kg of seeds gave a considerable effect on the growth characters of cowpea plant during the two seasons. The best growth of cowpea plant , as expressed by fresh and dry weight of whole plant and its different parts recorded its highest values when chemical phosphorus at rate of 300 kg/fed. was added and Bio-phosporus (phosphorine) was applied at rate of 21 g/kg of seeds . The highest concentration N, P and K in leaf and/or shoot tissues were recorded when phosphorine at rate of 21 g/kg of seeds as well as chemical phosphorus fertilizer at rate of 300 kg/feddan were added. Addition of chemical phosphorus as super phosphate at rate upto 300 kg/fed. had a significant increase in total yield of dry seeds .Also the interaction treatments of chemical X bio-phosphorus fertilizers caused an increase in total yield of dry seeds .