One-day, 4-day and 7-day old eggs of bivoltine silkworm, Bombyx mori L. (P 5 race) were treated by aqueous solutions of ascorbic acid, biotin, bovine serum albumin, theophylline, 5-HT and c-AMP at the concentrations of 2 mg/ml, 1.5mg/ml, 2 mg/ml, 1.5 mg/ml, 2 mg/ml and 1.5 mg/ml, respectively and subsequent to treatments different economic parameters of the silkworms were studied. Except ascorbic acid all chemicals improved larval and cocoon weight and effect of 5-HT was pronounced (41.46g/10 larvae; 2.026g/cocoon). However, improvement in pupal weight was effected except ascorbic acid and c-AMP. None of the biologically active chemicals exhibited any major effect on shell weight and SR% while all improved ERR%. Noticeable effect of 7-days old egg treatment was obtained in all characters except ERR% where treatment at 4-day egg revealed significant improvement.