A study on population dynamics of chilli thrips, Scirtothrips dorsalis Hood in relation to abiotic factors was carried out at Main Vegetable Research Station, Anand Agricultural University, Anand (Gujarat) during kharif season of 2002-03 and 2003-04. Results revealed that the incidence of  S. dorsalis on chilli crop commenced from first week of September and continued up to harvest of the crops being peak activity was recorded in November (4.99 to 5.54 thrips/leaf) and February–March ( 5.29 to 7.38 thrips/leaf). Correlation coefficient values worked out for thrips incidence and weather parameters revealed that significant positive relationship existed with bright sun shine hours and maximum temperature whereas significant negative correlation was found with morning, afternoon and mean relative humidity, morning, afternoon and mean vapour pressure as well as rainfall. On the basis of regression study, an equation of  Y=9.273-0.026* RF-0.146** RH2 (Where, RF= Rainfall and RH2= Afternoon Relative humidity) was fitted. The values of coefficient of determination (R2) was worked out to the tune of 0.89. Among the different abiotic factors studied, decrease in afternoon relative humidity (between the range of 20 to 40 %) helped in build up of the pest population, whereas thrips population decreased with increasing rainfall.