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 (ie, 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. Integrating effect sizes from 91 published and unpublished experimental studies that include both an incidental-affect induction and neutral-control condition (k= 271 effect sizes: k= 183 negative affect, k= 78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 (eg, intentions, evaluations, craving, perceived control). 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. 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.