Abstract Introduction Tobacco cigarette smoking a well-known cause of cancer and other diseases. Hookah smoking is another form of tobacco use that has rapidly spread in the United State and Europe. This study assessed beliefs about the harmfulness of smoking hookah. Methods We surveyed hookah users in all cafes that provided hookah to its customers in downtown San Diego, California and nearby areas. A total of 235 hookah users participated in this study. Results Average age of study participants was 22 years, 57% were males, and 72% were not cigarette smokers. Whites were more likely to use hookah than the other ethnic groups (33%), older hookah users (26-35 years) were mostly males, and mint flavor of hookah tobacco was the most popular among a wide variety of flavors (23%). There was no significant difference in gender in relation to the wrong perception that hookah is less harmful than cigarettes, but those of Asian ethnicity were much less likely than other ethnic groups to believe that hookah is less harmful than cigarettes. More frequent users of hookah were more likely to believe that hookah is less harmful than cigarettes. The majority of hookah users (58.3%) believe hookah is less harmful than cigarette smoking. Discussion Compared to cigarettes, there appears to be a lack of knowledge about the harmfulness of smoking hookah among users regardless of their demographic background. Education about the harmfulness of smoking hookah and policies to limit its use should be implemented to prevent the spread of this new form of tobacco use.