The effects of phosphorus fertilizer and weed control on yield and major yield components of faba bean (Vicia faba L.) were studied on Nitisols of Ethiopian highlands. Factorial combinations of four levels of phosphorus fertilizer (0, 10, 20 and 30 kg P ha-1) as triple super phosphate (TSP) and two levels of weeding (W1 = no weeding and W2 = hand weeding once six weeks after crop emergence) were laid out in randomized complete block design with three replications. Results indicated that highly significant positive responses of number of pods per plant, total biomass and seed yields of faba bean to phosphorus fertilizer and weeding treatments were noted. Phosphorus level × weed control interaction over three years significantly (P ≤ 0.05) affected faba bean seed yield at Rob Gebeya but not at Welmera. Phosphorus application at the rates of 10, 20 and 30 kg P ha-1 resulted in mean seed yield increases compared to the control of 20, 41 and 53%, respectively on the average of locations; 13, 33 and 51%, respectively at Welmera, and 26, 48 and 55%, respectively at Rob Gebeya.Weeding once increased mean seed yields of faba bean by 25% on the average (35 and 17% at Welmera and Rob Gebeya, respectively) compared to unweeded check. Seed yield was positively correlated with total biomass and number of pods per plant (r = 0.95*** and 0.75***, respectively) at Welmera, and (r = 0.94*** and 0.55**, respectively) at Rob Gebeya. The results of economic analysis indicated that the highest marginal rate of return was obtained from weeding once six weeks after crop emergence and application of 20 kg P ha-1, which is economically the most feasible alternative on Nitisols of central Ethiopian highlands.