Risk-taking behavior often has uncertain outcomes, which can sometimes be harmful. However, risk behavior presumably evolved due to its advantageousness. A comparative approach can help us better understand the evolution of risky decision-making and its underlying mechanisms. Literature suggests that increased risk-taking is associated with elevated testosterone levels, but this finding is inconsistent. Other literature suggests that cortisol influences the relationship between testosterone and risk-taking behavior. The Balloon Analogue Risk Task (BART) is a standardized task that assesses risk-taking behavior in humans. I created a modified BART for standardized assessment of risk-taking behavior in adults, children, and nonhuman primates. The modified BART was validated in adults, and used to assess the relationship between capuchin monkey risk behavior, testosterone, and cortisol levels. There was no relationship between hormones and risk behavior in capuchins. Future research should investigate the relationship between hormones and risk behavior in nonhuman primates with different mating systems.