This study evaluated the affective and neural mechanisms supporting the effects of Savoring Meditation (SAV) on pain processing in patients with rheumatoid arthritis. SAV was designed to help patients with chronic pain attend to the multisensory experiences engendered by meditating on a personally meaningful positive emotional memory. We hypothesized that, relative to a non-mindful breathing (NMB) control, SAV would increase positive emotions, reduce anhedonia, and engage the corticostriatal circuits, a network of brain regions associated with appraisals of rewarding and aversive stimuli. Target corticostriatal regions included the nucleus accumbens (NAc) and the dorsolateral prefrontal cortex (DLPFC). Patients were randomized to a brief 4-session (20 minutes each) course of SAV (n=21; n=17 with complete imaging data) or the NMB control (n=23; n=18 with complete imaging data). At post-intervention, mechanistic outcomes were assessed with functional MRI using a perfusion-based arterial spin labeling technique during noxious thermal stimulation to determine if SAV was associated with corticostriatal activation when compared to rest, with NMB serving as a between-person control group. Positive emotions were assessed with the Positive and Negative Affect Schedule-X. Anhedonia was assessed with the Snaith-Hamilton Pleasure Scale. Whole-brain analysis resulted in a 3-way interaction of Group (SAV vs. NMB) X Pain (Heat vs. Warm) X Practice (Meditating vs. Rest), revealing a significant increase in activation in the right NAc (p=.020), and deactivation in the right DLPFC (p<.001) while practicing SAV during noxious thermal stimulation. Patients in SAV reported lower overall experimental pain than those in NMB (p=.049). Group X Time interactions revealed greater increases in Joviality (p=.020) and Serenity (p=.040), and decreases in anhedonia (p=.030), in SAV vs. NMB. SAV is a promising brief meditation intervention for augmenting reward processing and positive emotions as a means of regulating pain. Grant support from NIH/NCCIH R61AT010134.