After implementing measures to control lead pollution in many countries, blood lead levels (BLLs) in children have been declined. The phase-out of leaded petrol began in Lucknow, the capital of most populated state, Uttar Pradesh in India on April 1, 2000. We evaluated the mean BLL and associated risk factors for lead exposure in Lucknow children (3-12 years) after petrol lead phase-out activity. The mean BLL of the 200 children was 9.3 microg/dL (range: 1.0-27.9 microg/dL). Seventy-four children (37%) had BLL above the Centre for Disease Control and Prevention's (CDC) level of concern (10 microg/dL). When these data were compared with BLLs determined by the George Foundation among the children of Mumbai, Bangalore, Kolkata, Chennai, Hyderabad, and Delhi during the year 1997 when leaded petrol was in use, where 62%, 62%, 87%, 96%, 43%, and 95%, respectively, then exceeded the CDC intervention level. Further, BLL of present study was very close to Mumbai children (age < or =12 years) estimated following the introduction of unleaded petrol, and 33% children had BLL above the CDC concern level with an average 8.4 microg/dL. Low socioeconomic status, proximity of home to traffic density, and mother's illiteracy were the factors associated with elevated BLLs in Lucknow children (P < 0.05). Overall, results indicate a declining trend of BLL in Lucknow children when compared with those reported from other cities of India when leaded petrol was in practice. A national population-based study is recommended to determine the prevalence of elevated BLLs after the phase-out of leaded-petrol. In addition, future studies on other sources of lead exposure in Lucknow are warranted for public health purposes.