Abstract: Dry seeds of groundnut (Arachis hypogaea) varieties Samnut 10 and Samnut 20 obtained from the Ministry of Agriculture, Ilorin, Nigeria were treated with sodium azide concentrations (10, 20, 30, 40 and 50 mM) to evaluate the vegetative and yield performances of the varieties in response to treatment. Low concentrations (10-30 mM) promoted fast germination, though germination, percentage germination and seedling survival decreased with increased in concentrations. Highest vegetative growth was induced by 50 mM concentration 2-week after sowing (WAS) and correlations were established performances of the two varieties in relation to different concentrations of sodium azide. The plant vegetative traits evaluated at 4WAS, 6WAS, and 8WAS showed significance responses to different treatment concentrations. Highest performance was obtained at 50 mM, the trend which was sustained till maturity. Early maturity was achieved in all the concentrations applied and quantitative yield parameters evaluated were highest among 50 mM treated plants. In general, the performances of the two varieties were optimal in responses to 50 mM concentration and both varieties (Samnut 10 and Samnut 20) responded similarly to sodium azide treatment of different concentrations. These findings suggest that sodium azide can be utilised to create variability among existing germplasm for improving vegetative and yield parameters of groundnut.