Three F7 tomato progenies obtained from the HT-16 cross in the INPA Department of Agronomy Sciences breeding program were evaluated for fruit-setting ability. The trials were realized in a greenhouse, with a transparent plastic cover, during 37 days, which covered all the flowering and fruiting phases from the first to the eighth cluster; the greenhouse air temperature was mesured with a thermohygrograph. The temperature variation was from 19° C (minimum) to 43° C (maximum). The results showed the occurrence of genetic variability among and within progenies for fruit-setting percentage and making possible Its exploitation in the breeding process to obtain lines with high fruit-setting ability under conditions of high