A laboratory experiment was conducted to evaluate the interaction effect of phosphorus and selenium application rates on their availability in three different soil types with time. The soil samples were collected from the surface layers "0-30 cm" of three different sites. Four levels from Se were used as followed 0.0 – 0.5 - 1.0 and 2.0 mg Se kg ^-1 soil as sodium selenate while P was used as mono super phosphate at rates of 0.0 – 3.225 – 6.45 and 12.9 mg P kg^-1 soil and they were incubated with soil for one month. Results revealed a positive and significant correlation between Se and P application rates as well as time of incubation on soil available Se; where soil available Se content was increased with increasing the application rate of Se especially when P was also added at high rates as time of incubation was passed. The highest soil available Se values were obtained when Se and P were added at rates of 2 and 12.9 mg kg^-1 soil, respectively especially in the case of soil 3 (clayey soil). Results also showed that soil available phosphorus was positively but not significant affected with increasing the application level of both Se and P, but it was negatively affected as the time of incubation was increased.