Urinary 1-hydroxypyrene has been shown to be a reliable biomarker for polynuclear aromatic hydrocarbon exposure. In urine samples 1-hydroxypyrene is found both as free and as bound with glucuronide to yield a 1- hydroxypyrene-glucuronide adduct. In this study the extent of exposure to polynuclear aromatic hydrocarbons in occupationally exposed subjects was studied by measuring free urinary 1-hydroxypyrene levels. This was done using reversed phase HPLC with a UV detector at wavelength of 242nm. The urine samples were collected from subjects who work as Petrol StationAttendants andAuto Mechanics in Lagos area of Nigeria. These subjects are exposed to vast amount of polynuclear aromatic hydrocarbons as a result of their occupation. This pilot study was carried out on 13 adultmale subjects who are made up of smokers and non smokers. The level of 1-hydroxypyrene in the urine samples of these subjects ranged from 0.1 to 1.3 ug/ml. There seem to be no correlation with years of exposure to the level of 1-hydroxypyrene found in the urine samples.