Parthenium (Parthenium hysterophorus L.) is a new encroacher weed into many crops including sorghum. An attempt was made to analyse the growth of parthenium and other weeds in sorghum. In sorghum, Trianthema portulacastrum, Acrachne racemosa, Dactyloctenium aegyptium, Digera arvensis and Tribulus terrestris exhibited much higher population and dry weight than parthenium. Parthenium had inferior growth in terms of population and dry weight at 30, 60 and 90 DAS compared to most other weeds. But its weed growth rate (WGR) and weed relative growth rate (WRGR) were on the increase consistently till 90 DAS. The reverse was true for other weeds, whose growth rates (WGR and WRGR) decreased gradually over time.