The effect of constant temperature on the development, reproduction and population growth of Aculops lycopersici reared on a tomato leaflet was investigated. Survival rates from egg to adult were more than 69% at temperatures between 15°C and 27.5°C, but only 53% at 30°C. Developmental rates increased linearly as rearing temperature increased from 15°C to 27.5°C. A total of 81.2 degree-days above a developmental zero of 10.5°C were required to complete development from egg to adult emergence. Adult longevity decreased with increasing temperature. Fecundity was highest at 25°C with 51.7 eggs per female. The highest intrinsic rate of natural increase was observed at 25°C as 0.253 per day.