Samia cynthia ricini is a type of silkworm with a high reproductive capacity. Population management is a strategic step that can be taken to carry out mass multiplication activities effectively, efficiently, and support a sustainable production system. Population management can be done by modifying the egg or pupal stages. This research intends to examine the effect of pupal cooling on the growth period of pupae and adults of S. c. ricini and its fecundity. The study was conducted by cooling the pupae of S. c. ricini for 1-7 days at five-degree Celsius. After that, the pupae are maintained at room temperature until they become adults and die. The results showed that cooling time could delay the pupal stage by up to 8 days. However, it does not affect adults’ growth period or fecundity.