The effect of mutagens on pollen sterility in the first filial generation of grasspea (Lathyrus sativus Linn.) was studied during 2 yr of experimental work (2012 and 2013) at Fergusson College, Pune, India. Seed of the first filial generation of grasspea (Lathyrus sativus Linn.) was treated with ethyl methanesulphonate (EMS), a chemical mutagen, at four concentrations (5 mM, 10 mM, 15 mM and 20 mM) and with physical mutagen gamma rays at four dosages (100 Gy, 200 Gy, 300 Gy and 400 Gy), and combinations of gamma rays and EMS using four treatments (100 Gy + 10 mM, 200 Gy + 10 mM, 300 Gy + 10 mM, and 400 Gy + 10 mM). Results indicated that increased pollen sterility was associated with corresponding increases in dose/concentration of mutagens. Maximum pollen sterility (25.54%) was observed... in combination gamma rays with EMS (400 Gy + 10 mM) treatment and the minimum pollen sterility (10.53%) was observed in gamma rays (100 Gy) treatment.