The lentil (Lens culinaris Medik.) belongs to the most important leguminous plants in Asia. It is a very popular and highly nutritious food. However, small pod size and low yield limit its agricultural use. Through irradiation mutagenesis of dry lentil seeds by 12 C 6+ ion beam, we found some lines with excellent agricultural traits in M2 progeny at doses of 90 Gy (grey), such as height increase and improvement of the number of branches and three-seed pods as well as seeds with increased grain yield. Six generations of irradiated lentils were screened for these traits. In the M8 generation, the grain yield of three high-yielding lentil lines (lines hyl-1, hyl-2, and hyl-3) reached 212. 4%, 195.3% and 190.8%, respectively, of the non-irradiated controls. The results indicated that crop improvement was stable inherited across the generations. Statistical analysis revealed that the increase in grain yield was due to increased total pod number and seeds per pod. Fortunately, adverse effects of irradiation (e.g. reduced germination rates and poor pollen vitality) disappeared over the eight generations. In conclusion, we present a practical method for the improvement of lentils through radiation breeding, leading to high yielding cultivars, which could support the use of this crop in agriculture.