Source apportionment of particulate matter (PM) has been carried out for the city of Hyderabad using the chemical mass balance model (CMB8, Ver. 8.0) in PM10 and PM2.5 size modes. Urban particles were collected using Continuous Particulate Matter Analyzer (TEOM) during different seasons conducted in Punjagutta site, a critical traffic corridor, during June 2004–May 2005. The measurement of PM10 & PM2.5 at the site is measured throughout the day. Samples were collected in every 15 min; additionally instrument computes the total mass accumulation for every 30 min, 1-h, 8-h and 24 h average mass concentrations. Chemical characterization of PM10 & PM2.5 was done by ICP-MS. Source apportionment studies were carried out to quantify the possible sources affecting region using CMB Model Ver. 8.o. The CMB8 executed separately for both coarse and fine sizes. Results obtained by CMB indicate the dominance of resuspended dust (40%), followed by vehicular pollution (22%), combustion (12%), industrial (9%) and refuse burning (7%) in PM10; while in PM2.5 vehicular pollution (31%) dominated over resuspended dust (26%), combustion (9%), industrial (7%) and refuse burning (6%).