Background/Objective: Impaired Inhibitory Control (IC) is a core feature of psychotic disorders and is related with impaired social functioning in people experiencing psychosis. Despite research showing the benefits of mindfulness over IC in the general population, no study has assessed its effects on IC in psychoses. The aim of our study was to assess the effectiveness of a mindfulness-based intervention combined with integrated rehabilitation treatment in a sample of people diagnosed of psychotic disorders. Method: Fifty-six patients diagnosed with psychotic disorder were recruited and randomly allocated either to integrated rehabilitation treatment or integrated rehabilitation treatment enhanced with 26 mindfulness group sessions. Measures comprised PANSS interview, MAAS scale, and Stroop Color Word Test (SCWT). The primary outcome variable was the performance in the non-congruent trials of the SCWT. Results: There were no differences between groups at baseline. At post-treatment patients allocated to mindfulness group increased their scores in non-congruent trials of SCWT and in MAAS. At post-treatment mindfulness group scored higher than integrated rehabilitation treatment in MAAS. Conclusions: Data suggest that mindfulness added to integrated rehabilitation treatment may improve IC in psychosis. Results are convergent with prior works about the effect of mindfulness over cognitive performance in general population.