As a result of mutation induction by using two chemomutagenes-sodium azide (NaN3) and N-nitroso-N- methy- lurea (MNU) as well as laser light, numerous mutants of grass pea (Lathyrus sativus L.) were obtained. Initial material for the study was constituted by seeds of two Polish cultivars – Derek and Krab. For analyses of trait variation in a field trial and of the physical properties of seeds, 20 morphological mutants were chosen as well as the two above mentioned initial cultivars. The results obtained from the field trial indicate a broader genetic variation of traits for the mutants as compared to the initial cultivars. Some of the most interesting and desirable mutants were characterized by a decrease of plant height, a higher location of the lowest pod, and a reduction of lateral branches and biomass. Those traits resulted in better lodging resistance as well as in more uniform and earlier maturity. With reference to parameters of yield structure, some of the mutants exceeded their initial forms. A broad spectrum of variability was also observed for the physical properties of seeds, such as: seed thickness, weight of 1000 seeds and resistance to static compression. The mutants, in comparison to the initial cultivars, were characterized by higher or lower values of compressive strength as expressed by force, deformation and energy.