This research deals with the effect of (NH4)2 SO4 (ammonium sulphate) and exogenous growth regulators on weight average of fruit of tomato cultivars "Angela" and "Roma". In two experiments, (NH4)2 SO4 (2g/l soil), succinic acid -2,2_ dimethylhydrazide (SADH) 3000 ppm, SADH plus (NH4)2 SO4, (2-chloroethyl) trimethylammonium chloride (CCC) 2000 ppm, CCC plus (NH4)2 SO4, gibberellic acid (GA) 100 ppm, GA plus (NH4)2 SO4, and check treatment, were applied. In two other experiments, 1-(2,4-dichloraphen-oxyaedthyl) -3,5-dimethyl pyrazole at concentrations of 3,75, 15,00 and 7,5 ppm, and (2-chloroethyl) phosphonic acid (CEPA) 500, 1000 and 1500 ppm, were used. It was observed that SADH promotes reduction in the weight average of fruit of tomato "Angela" in relation to treatment with (NH4)2 SO4. Ammonium sulphate in the soil reduced the detrimental effects of foliar application of SADH. Tomato plants "Angela" and "Roma" sprayed with CCC, GA, Tomakon and CEPA did not show variation in the weight average of fruit.