Objective: To develop a lifestyle risk scale (LRS) of health-related behaviors based on risk assessments of study participants. Method: By means of pairwise comparisons of assessed risks associated with tobacco, alcohol, obesity, fast-food, physical inactivity, and lack of sleep, each at four levels, 24 behaviors were ranked on a unidimensional risk scale. Results: Overall, use of tobacco was assigned the highest risk score (3.7), consumption of fast-food and lack of sleep the lowest (1.7, 1.6). Minor risk factors (lack of sleep and fast-food) were, at their highest levels, assigned similar risk values as major risk factors (tobacco, alcohol, obesity) at their lowest levels. Lifestyles of female participants were less hazardous than those of male participants, as measured with the LRS. In contrast, perception of behavioral health risks was more precise in men. Conclusions: The LRS provides a practical quantification to identify and compare groups with different risk behavior patterns as well as clusters of risky health behaviors in and across populations. It can also support the communication of behavioral health risks.