Abstract: Seven exotic and three local ash gourd genotypes were studied to evaluate their floral biology. It was observed that the first male flowers of exotic materials except Bisexual opened within 33-34 days and female flowers within 35-36 days from seed sowing and their node number were 5-9 and 5-13, respectively. For first female flower opening lowest plant heights were observed 93.11 cm (High female), 99.9 cm (Chiqua-9) and 106 cm (Chiqua-90-10). However, incase of the local materials 56.8-58.9 days for first male flower opening, 58.6-63.3 days for first female flower opening were required. In local materials plant heights at first female flower opening were 306.1-324.1 cm. The Bisexual produced first hermaphrodite flower at the height of 200.4 cm. Anthesis of male flowers required 4 days and female flowers required 5 days from visible appearance of flower buds for all types. Maximum number of fruits (7.8) per plant as well as the highest percentage of fruit set (74.30%) was found in the genotype Chiqua-90-10. The lowest percentage of fruit set (13%) was observed in the Bisexual which produced the highest number of hermaphrodite flowers (11.5). In all genotype the anthesis of staminate flowers started within the range of 4:33 to 4:45 am and required 20 to 30 min for full blooming. The anthesis of female flowers started from 4:20 to 4:30 am and required 20-25 min for full blooming. Anther dehiscence of all genotypes took place within 1:45 to 2:40 am i.e., 2 h before anthesis. The stigma became receptive 6 h before anthesis and remained so till 16 h after anthesis in all monoecious ash gourds. All the genotypes were cross compatible for each another and in all directions. Pollen grains remain viable up to 20 h after anthesis.