The effect of temperature on the development of the cotton caterpillar, Diaphania indica (Saunders) was examined by rearing cohorts on cucumber Cucumis sativus L. leaves at various constant temperatures. The developmental periods were 47.4, 24.4, 18.2 and 19.7 d at 20, 25, 30 and 35°C, respectively. The lower threshold temperature and total effective temperature for development of the pre-adult stage were determined to be 13.5°C and 294.1 degree days, respectively. At 25°C, the mean adult longevity of males (21.6 d) was significantly longer than that of females (16.7 d). Pre-oviposition and oviposition periods were 1.04 d and 14.8 d, respectively. The total number of eggs produced per female was 808.7. Pupal weights and total numbers of eggs oviposited were positively correlated. The intrinsic rate of natural increase (rc) was 0.20 per day.