To estimate the effect of large scale tobacco sponsorship of cricket, a study was conducted on children's knowledge and perceptions about smoking and their impact on subsequent smoking uptake. Twelve nations played 36 matched in the Wills World Cup-1996 cricket series over one month during which Wills (a cigarette brand) was extensively advertised by live broadcast to a 2-billion viewers with WILLS logo on the players' T-shirts and playground, newspapers, magazines, and hoardings. An anonymous structured questionnaire including 4 knowledge based questions about tobacco, 4 about perceptions directly promoted by Wills and 10 questions related to wrong perceptions about smoking was administered by class teachers six months after the series. A total of 5822 children (65% boys and 35% girls) in Grade 10, aged 13-17 years (median 14) were selected. Smokers increased from 137 (2.4%) before the series to 649 (11.1%) after the series. The smoking initiation rate was 2.04% (13/636) in children with full knowledge and no wrong perceptions, 7.8% (48/618) among those with less knowledge and no wrong perceptions. Among those with less knowledge but believing in at least 2 of Wills related perceptions and 3 of the smoking related perceptions the rate for smoking initiation was 20.55% (127/618). The sponsorship appeared to have a similar effect on initiation rates in both sexes despite the strong social taboo against girls smoking in India. Wrong perceptions about smoking promoted by tobacco sponsorship increases smoking initiation amongst both boys and girls even when they are aware of the risks involved. The study suggests that education, without bans on advertisements is unlikely to stop initiation of smoking among children.