The present study was directed to evaluate the effect of temperature and Lambda-cyhalothrin residues on development of the immature stages of the two-spotted spider mite, Tetranychus urticae Koch. Development of T. urticae immature stages was measured at 18, 22, 26 and 30ºC. An increase in the rate of development was noticed at 18ºC. The duration from the egg to each of the successive stages in the life cycle was found to be at least 2.3 times as long as the duration at 30ºC. The duration of development in hours from egg to adult at 26ºC and 30ºC showed no significant differences, and indeed it was virtually identical. By increasing the temperature, the records showed highly significant decrease in the total developmental time, as well as in the durations of different stages in the life cycle. The time required to reach the adult stage increased due to the presence of the sublethal concentrations of Lambda-cyhalothrin. The duration of larval and protonymphal stages (as means) were considerably longer in the mites exposed to Lambda-cyhalothrin. Mortality counts recorded for LC₅₀ concentration (65.79 ppm) on adults was also greater in the mites exposed to the  tested  insecticide.