The present study was carried out in Plant Biotechnology Research Laboratory at Institute of Biotechnology and Genetic Engineering, University of Sindh, Jamshoro. In this study mutagenic effect of sodium azide on a local variety of tomato (Lycopersicon esculentum Mill.) was observed. Tomato seeds were treated with sodium azide (0.1% and 0.2% concentration) for 11/2 hour. Effect was checked both through invitro conditions and invivo conditions. It was observed that germination was adversely affected in the treatments as compared to the control. 0.1% NaN3 showed lower germination percentage i.e. 34.37% on MS medium and 58% in field conditions while 0.2% NaN3 showed 67.5% on MS media and 61% in field conditions. The fresh and dry weight was measured initially after 4 weeks and than after 2 months which showed higher value of fresh and dry weight for 0.2% NaN3 initially while after 2 months (0.2% NaN3)plants growth rate was low and fresh and dry weight of plants treated with 0.1% NaN3 was higher (7.087g) fresh weight and (0.803g) dry weight. MS media plantlets showed decrease in fresh and dry weight with increasing sodium azide concentration. Shoot length initially showed higher value