Prescription opioid misuse among chronic pain patients is associated with self-regulatory deficits, affective distress and opioid cue reactivity. Dispositional mindfulness has been associated with enhanced self-regulation, lower distress, and adaptive autonomic responses following drug cue exposure. We hypothesized that dispositional mindfulness might serve as a protective factor among opioid-treated chronic pain patients. We examined heart rate variability (HRV) during exposure to opioid cues and depressed mood as mediators of the association between dispositional mindfulness and opioid craving. Data were obtained from a sample of chronic pain patients (N=115) receiving long-term opioid pharmacotherapy. Participants self-reported opioid craving and depression, and HRV was measured during an opioid-cue dot probe task. Dispositional mindfulness was significantly positively correlated with HRV, and HRV was significantly inversely associated with opioid craving. Dispositional mindfulness was significantly negatively correlated with depression, and depression was significantly positively correlated with opioid craving. Path analysis revealed significant indirect effects of dispositional mindfulness on craving through both HRV and depression. Dispositional mindfulness may buffer against opioid craving among chronic pain patients prescribed opioids; this buffering effect may be a function of improved autonomic and affective responses.