The optimum temperature and period of leaf wetness requirement for Ascochyta blight development in one month old chickpea plants of resistant (EI00Y) lIIld susceptible (H208) genotypes were studied after inoculation with two Ascochyta rabiej isolates. The shortest period of leaf wetness needed for successful infection was 36 hours at 200C in susceptible genotype. However, the leaf wetness period required for successful infection in resistant genotype was 60 hours. The maximum infection was recorded when the temperature was 200C with a period of leaf wetness of 72 hours.