To assess plant breeding, the genetic variability plays an important role which forms the basis for any crop improvement program. The statistical analysis of Genetic variability, Phenotypic coefficient of variation (PCV), Genotypic coefficient of variation (GCV), Heritability (h²) and Genetic advance (GA) was studied for its yield and yield contributing characters like plant height, number of branches per plant, number of pods per plant, length of pod, number of seeds per pod, number of seeds per plant and 100 seed weight. Statistical analysis gives information about the character wise genetic improvement of plants through mutagenesis experiments. For the calculation of different yield and yield contributing traits in Phaseolus lunatus L. (lima bean), mutagenic treatments Gamma rays, EMS and combination were used to induce genetic variability. The Genetic variability observed in plants is due to the environmental influence and genetic factors. It could also be due to the interaction between these two factors. There was positive and negative shift of mean for various traits in different mutagenic treatments. The difference between PCV and GCV values were high for parameters like number of seeds per pod and number of branches per plant in Phaseolus lunatus L. Higher the presence of PCV and GCV greater the variability of all the traits which indicates scope for improvement of traits by simple selection. High heritability when coupled with genetic advance is more useful in understanding the selection process.