Optimum impregnation ratio of rock phosphate (RP) and compost in RP-enriched organic fertilizer, its time and rate of application to the crop plants affect the availability of nutrients through the process of mineralization and immobilization. A series of pot and field experiments were conducted to investigate the comparative efficacy of RP-enriched organic fertilizer vs. mineral phosphatic fertilizer on growth, yield and nodulation of lentil. Optimum impregnation ratio of RP and compost and the time of application to improve growth, nodulation and yield of lentil were investigated under wire house conditions. The impregnation ratio of 50:50 RP and compost and time of application of seven days before sowing resulted in the maximum nodulation, growth and yield parameters compared to the other impregnation ratios and the times of application. Optimized impregnation ratio and time of application were further investigated for optimum rate of application under field conditions to enhance nodulation, growth and yield of lentil in comparison with recommended mineral phosphatic fertilizer. The application of RP-enriched organic fertilizer @ 1000 kg ha-1 showed an increase of 35.5, 27 and 6% in number of nodules, fresh weight of nodules, and grain yield compared to chemical phosphatic fertilizer, respectively. Similarly, significant increase in P contents of straw and grain was also observed with the application of RP-enriched organic fertilizer @ 1000 kg ha-1 compared to chemical phosphatic fertilizer. However, the effect of the application of 800 and 1000 kg ha-1 was statistically non-significant for most of the parameters studied. The results suggested that RP-enriched organic fertilizer with optimum impregnation ratio of RP and compost, time of application and rate of application had a pronounced effect on nodulation, growth and yield of lentil as compared to recommended chemical phosphatic fertilizer.