In order to assess the influence of temperature on the acute toxicity of Dimethoate 30% EC on mulberry silkworm, Bombyx mori (Linnaeus, 1758), a laboratory study was conducted under three temperature conditions viz., 20±1°C, 25±1°C, 30±1°C with a constant range of relative humidity from 60 to 80%. Identical concentrations of Dimethoate 30% EC viz, 125, 250, 500, 1000, 2000 and 4000 ppm were prepared in deionised water and evaluated on the early 3rd instar larvae of silkworm by following leaf dip method. The larvae were exposed to treated mulberry leaves for 24 hours and incubated separately under different temperature conditions. Observation on larval mortality was made on 24 and 48 hours after treatment. The results of the experiment showed that there was a temperature response toxic effect noticed on the silkworm larvae. The 48 hour LC50 values of Dimethoate 30% EC were 1322, 1242, 997 ppm for 20±1°C, 25±1°C, 30±1°C respectively. Similarly the LC95 values were 4319, 3521, 2217 ppm respectively. The 48 hour LC50 and LC95 values of Dimethoate 30% EC were significantly minimum at higher temperature range tested (30±1°C). It is concluded that the temperature has a pronounced effect on toxicity of Dimethoate 30% EC on silkworm.