The objective of our study was to analyze the perceived (belief) or adopted (behavior) measures to reduce cancer risk in a Spanish population. We used cross-sectional data from the Cornella Health Interview Survey Follow-up Study (CHIS.FU). We analyzed 1,438 subjects who in 2002 answered questions about risk perceptions on cancer and related behavior (668 males and 770 females). The benefits of avoiding cigarette smoking (95.8%), sunlight exposure (94.9%) and alcohol (81.0%) were widely recognized. On the other hand, electromagnetic fields (92.1%), food coloring and other food additives (78.4%) or pesticides (69.4%), whose role in cancer occurrence, if any, remain unproven, were clearly considered as cancer risk factors in this population. Compared to men, women more frequently reported healthy behaviors, and the role of exogenous factors (i.e., environmental risk factors) were widely popular. There was a socioeconomic gradient on cancer risk perception with respect to several lifestyle or dietary factors. Individuals with higher educational level scored lower in several risk factors than those with primary or less than primary school education. Smokers reported adopting fewer healthy behaviors than former or never smokers. How people perceive health issues and risk or make choices about their own behavior does not always follow a predictable or rational pattern.