Aganaspis pelleranoi (Brèthes, 1924) (Hymenoptera: Figitidae) is a koinobiont endoparasitoid of larvae of species of the genus Anastrepha and of Ceratitis capitata. It is a candidate for use as a biological control agent, as under field conditions, it may reach a parasitism rate of 62%. The objective of this study was to determine the effect of different constant temperatures on biological parameters of A. pelleranoi when parasitizing the larva of Anastrepha fraterculus (Wiedemann, 1830) (Diptera: Tephritidae), as well as to determine its thermal requirements. The study was conducted in environmental chambers at 18, 20, 22, 25, 28, and 30 ± 1°C; 70 ± 10% relative humidity; and a 12-h photophase. Females maintained at 18 and 20°C produced more progeny than females at other temperatures tested. The longevity of males and females was inversely proportional to temperature, ranging from 49.1 to 3.73 d for females and from 32.1 to 3.8 d for males at temperatures of 18–30°C, respectively. The duration of the biological cycle (egg-to-adult) was influenced by temperature, and ranged from 69.1 d at 18°C to 30 d at 25°C. No preimaginal development of A. pelleranoi occurred at 28 and 30°C. The relationship between temperature and the demographic parameters of A. pelleranoi showed a linear effect over the temperature range of 18–25°C. The lower temperature threshold and thermal constant were 11.69°C and 391.70 degree days,respectively.