In this study road side sediment samples were collected in Chennai-Bangalore National Highway (Tamilnadu, India) for a stretch starting from Sunguvarchatram and ending at Maduravoyal and subjected for heavy metal (Cd, Pb, Zn, Cr) analysis through Atomic Absorption Spectroscopy (AAS) Technique. Totally 30 sites were selected for sediment sample collection and sediment samples were collected as per standard methods. The concentration of heavy metals present in the road side sediments from the study area was determined by flame absorption Atomic Absorption Spectrophotometer AA7000. Toxicity factors such as Contamination Factor(CF) and Geo-accumulation Index (Igeo) were calculated using average continental crustal values for heavy metals1, 2. From the toxicity parameter results, it is observed that the contamination of the road side sediments in the study area by the metals Cd, Pb and Zn is mainly due to the anthropogenic activities (man-made activities) like industrial effluents, vehicular emission and wastages supplied to environment on the travel and uncontrolled input of sewage, garbage into the road side environment.