An experiment was conducted during rabi season of year 2011-12and 2012-13 at the entomological research farm, college of agriculture, RajMata VijyaRaje Scindia Agriculture university ,Gwalior(M.P.) to study the incidence of insect pests and their correlation between weather parameters. Mustard crop is dominantly attacked by mustard aphid, saw fly and painted bug. Mustard variety Rohini was sown in second week of November under normal agronomical condition during both the years i.e. 2011-12 and 2012-13.The activity of sawfly started from 44th SMW to 50th SMW with the peak population in 48th SMW .The activity of painted bug started from 44th SMW to 48th SMW with peak population (6.10bug/plant) in 46th SMW in the year 2011-12. In 2012-13 activity of painted bug started from 44th SMW to 49th SMW with peak population in 47th SMW (7.21 bugs /plant). Incidence of mustard aphid was observed in both the years at 51th SMW to 11th SMW . There were negative correlations between aphid population and temperature, whereas positive correlation with relative humidity, whereas effect of temperature was positive and that of RH was negative on painted bug.