|Cotton is one of the major cash crops of Pakistan. It suffers from severe yield losses because of various insect pests and diseases. Whiteflies and jassids are regarded as the key pests of cotton. Beside these, pink bollworm is also one of major devastators of this crop. Present study was conducted to evaluate the performance of Bt and non Bt varieties against these three major pests of cotton. Data were taken from upper, middle and lower leaves in case of sucking pests and for pink bollworm 5 plants were selected for determining its percent infestation. Data for CLCuD was computed using percent disease index (PDI). The results showed that non Bt varieties were heavily attacked by whiteflies with population above economic threshold level (ETL). Maximum mean population of 5.67 was recorded on NIAB-Karishma. Cotton jassid population was above ETL in all the varieties under study, with a maximum mean population of 1.80 on IR-NIAB-824. Moreover, population of pink bollworm was higher on Bt varieties as compared to the non Bt varieties with maximum mean percent infestation of 51.34% on Lalazar. The highest yield of 826 kg/acre was observed in NIAB-Karishma. All the tested varieties were highly susceptible to cotton leaf curl disease and there was no significant correlation of whitefly levels with percent disease index.