The link of betel, areca and chewable tobacco with head and neck cancers is clearly established. Fifty eight percent of the global head and neck cancers occur in South and Southeast Asia, where chewing of betel, areca and tobacco are common. This study was carried out to establish the pattern of use of Paan, Chaalia, Gutka, Niswar, Tumbaku and Naas among population of squatter settlement of Karachi and to determine the perceptions and knowledge regarding their role in the etiology of head and neck cancers. It was a cross-sectional study, performed at Bilal colony in Karachi. Through systematic sampling, 425 subjects [a male and female from a household] were interviewed with a structured questionnaire. Knowledge regarding etiology of head and neck cancers was classified in ordinals of ‘good’,‘some’and ‘poor’, for each substance separately, while practices were classified into ‘daily user’,‘occasional user’and’never user’. About 40% of the participants were chewing at least one item [betel, areca or tobacco products] on daily basis. This prevalence was 2.46 times higher among males than females and 1.39 times higher among adolescents than adults. At least 79% of the participants were classified as having poor knowledge about the carcinogenicity of each of these items. Knowledge increased with age and level of education. Health hazards of these items were poorly recognized and about 20% perceived at least one of these items to be beneficial. Positive attitudes were seen regarding the steps to curb the production, business and consumption of these substances. In conclusion, prevalence of chewing of betel, areca and tobacco among adults and adolescent is high. Deficiency in knowledge and wrong perception of favorable effect of chewing products is common. Besides curtailing the availability of chewing products, correct knowledge regarding its ill-effects should be inculcated among population to decrease the burden of head and neck cancers.