Stroke can have a range of physical, psychological, cognitive, and social impacts that are challenging for survivors. This study aimed to evaluate the efficacy of a group-based mindfulness intervention integrated into an inpatient rehabilitation program compared to standard care. A single-center, randomized, controlled trial was conducted in 93 poststroke patients. The intervention group received 6-weeks of mindfulness-based cognitive therapy (MBCT) and standard care; the control group received standard care. Primary outcomes were depression and trait anxiety; secondary outcomes were trait mindfulness and attention. Participants completed questionnaires at baseline, and postintervention (6 weeks). Mixed-effect model repeated measures analysis of variance was conducted between groups and across time. A total of 80 participants (intervention n  = 43; standard care n  = 37) were included in the postintervention analysis. There were no statistically significant differences in the primary outcomes between the groups over time. An improvement was found, however, on the trait mindfulness observing subscale in favor of the intervention group. Eight sessions of MBCT integrated into an inpatient stroke rehabilitation program over 6 weeks was not effective in improving depression and anxiety compared to standard care. Lack of follow-up and low to moderate pathological symptoms at baseline may have limited the effectiveness of this intervention.