Biology, ecology and damage potential of the sorghum midge,Contarinia sorghicolaCoquillet, were studied at Coimbatore, India. The life cycle of the midge was shorter in summer than winter: Johnson grass,Sorghum halepenseand pearl millet,Pennisetum americanumserved as alternate hosts for the sorghum midge. Seasonal incidence studies revealed that four peak infestations occurred in crops sown in April, June, August and October. Midge developmental stages were quite active all through the year with no diapause, Peak adult midge attraction to the light trap was recorded at 21.00 hours. However, adult midges were found to be quite active only in the daytime in the field. There was no relationship between adult midge catches from the light trap and the population recorded in the field. Morning relative humidity and wind velocity were negatively associated with the population of midge attracted to the light trap. An increased percentage of midge population was recorded in the light trap during the new moon and second quarter phases of moon. Sticky traps were not efficient in trapping adult midges. One pair of adult midge per earhead caused 16–9% grain damage.