A pot trial was performed in the summer seasons of 1997 and 1998 at the greenhouse of National Research Centre, , Dokki , Cairo, Egypt to study the effect of Rhizobiuminoculation, P , various salinity levels and their interactions on growth, yield and chemical composition of guar grown in sandy soil.  The obtained results show that Rhizobium inoculation, P- fertilization and their combinations significantly augmented growth parameters and the yield and its components, the highest increase was recorded due to the combined effect of both Rhizobiumand P. A remarkable decrease in growth and yield parameters was observed due to the high salinity levels (6000 & 8000 ppm) where the percentages of decrease reached 46.4% and 91.9% respectively in plant height. Plants treated with 8000 ppm salinity level failed to form any pods while the decrease in seed yield/ plant treated with 6000 ppm salinity level reached 72.4% compared to the control. Inclusion of both Rhizobium and P to different salinity levels mitigated their effects on plant growth and its yield, where the plants treated with 8000 ppm recovered their ability for pod formation. Chemical composition of seeds and mineral contents of leaves were increased owing to Rhizobiumand P- application except Na content in leaves. Gradual decrease was recorded N, P, K, Ca, Mg and Fe content in leaves with increasing salinity level while both Na and Zn were increased. The addition of both Rhizobium and P to the diverse salinity levels increased, to some extent, leaves content of N, P, K, Ca, Mg and Fe while relative decreases in Na content was recorded in comparison with the corresponding salinity levels.