The genetic diversity of grass pea genotypes from the collection of the Institute of Forage Crops - Pleven, Bulgaria was studied. The effect of the environment and genotype on the number of leaves per plant, fresh and dry root weight and dry root weight of the plant have been demonstrated. The genotype factor had a greater effect on the number of nodules per plant, the weight of the dry stems and the number of pods per plant, while the environment affected the number of leaves per plant, the fresh weight of the leaves and the number of seeds per plant. The phenotypic variation in number and weight of nodules, fresh weight of leaves and stems, number and weight of plant seeds and fresh weight of plant was found stronger, however the genotypic variation was stronger in the number of leaves, fresh and dry root weight, weight of dry stems and weight of dry root mass. The signs of fresh plant weight, fresh leaf weight, number of branches and weight of seeds per plant had high values of coefficient of inheritance and moderate genetic progress (GA), suggesting that the selection may be successful in improving them.