Objective: Appetitive risk behaviors (ARB), including tobacco use, alcohol consumption, consumption of calorie dense/nutrient-poor foods, and sexual risk behavior contribute substantially to morbidity and mortality. Affective states that arise from a wide array of unrelated circumstances (i.e., incidental affect) may carry over to influence ARB. A meta-analysis is needed to systematically examine causal evidence for the role of incidental affect (including specific emotions) in influencing ARB. Method: Integrating effect sizes from 91 published and unpublished experimental studies that include both an incidental-affect induction and neutral-control condition (k = 271 effect sizes: k = 183 negative affect, k = 78 positive affect), this meta-analysis examines how negative and positive affective states influenced ARB and related health cognitions (e.g., intentions, evaluations, craving, perceived control). Results: Negative affective states reliably increased ARB, in analyses where all negative affective states were analyzed (d = .29) and in stratified analyses of just negative mood (d = .30) and stress (d = .48). These effects were stronger among study populations coded as clinically at risk. Positive affective states generally did not influence ARB or related health cognitions, except in the presence of a craving cue. Design issues of extant literature largely precluded conclusions about the effects of specific positive and negative affective states. Conclusion: Taken together, findings suggest the importance of strategies to attenuate negative affect incidental to ARB to facilitate healthier behavioral patterns, especially among clinically at-risk individuals.