Abstract: An experiment was conducted at Masha District, Southwestern Ethiopia to investigate the effect of nitrogen and phosphorus rates on yield and yield components of potato. Four rates of nitrogen (0, 55, 110, 165 kg ha-1) and four rates of phosphorus (0, 20, 40, 60 kg ha-1) were combined in 4x4 factorial arrangement in randomized complete block design with three replications. Data collected on growth and yield parameters were analyzed using SAS 9.2 computer software. Application of 165 kg N ha-1 significantly increased days to flowering by 6 days, days to physiological maturity by 13 days, above ground biomass by 36%, underground biomass by 29.79%, total tuber yield by 60.33%, marketable tuber number by 56.36% and total tuber number by 31.7% and average tuber weight by 22.43%. However, N did not influence days to emergency, unmarketable tuber yield and unmarketable tuber number. Application of P significantly increased days to flowering by 3 days, above ground and underground biomass by 8.78% and 61.4% respectively and marketable tuber number by 19.72%. The interaction effect of 165 kg of N and 60 kg P increased marketable tuber yield (36 t ha-1) by 122% as compared to control (16.2 t ha-1). The result of this study verified that yield and yield components of potato are influenced by nitrogen and phosphorus rates. From this study, it can be concluded that the higher rates of nitrogen (165 kg ha-1) and phosphorus (60 kg ha-1) can be used for optimum production of potato variety Jalene in the study area Masha, Southwestern Ethiopia.