Flowering and fruiting of two varieties of bitter gourd (Tia and Biruttam) as affected by six levels of GA3 concentrations viz. 0, 25, 40, 55, 70 and 85 ppm was studied in the Crop Botany Field Laboratory of Bangladesh Agricultural University, Mymensingh during the period from February to May 2005. Application of GA3 at pre-flowering stage in bitter gourd plant significantly influenced flowering behaviour and fruting characteristics. It was observed that individual fruit weight were the maximum by application of GA3 at 40 ppm but at higher concentration (>40 ppm) fruit yield declined. The results showed that variety Tia produced higher yield (1.454 kg/plant) than the variety Biruttam (1.367 kg/plant). Effect of different level of GA3 concentrations were statistically different from each other.