Negative symptoms often inhibit the social integration of people suffering from schizophrenia. Reducing severe negative symptoms (SNS) in a clinically relevant way is a major unmet need. The aim of this study was to investigate whether Integrated Neurocognitive Therapy (INT), a group cognitive remediation therapy (CRT), reduces SNS in schizophrenia outpatients. INT was compared with Treatment As Usual (TAU) in a randomized-controlled trial (RCT). A total of 61 SNS outpatients participated in the study, 28 were allocated to the INT group and 33 to the TAU group. A test-battery was used at baseline, post-treatment at 15weeks, and 1-year-follow-up. Remission rates of SNS after therapy were significantly higher for INT compared to TAU. A trend favoring INT was obtained at follow-up. Furthermore, INT showed significantly higher functional outcome during follow-up compared to TAU. Regarding cognition, the strongest significant effect was found in attention post-treatment. No effects between groups on more complex neurocognition and social cognition were evident. SNS outpatients seem to accept INT group intervention as suggested by the high attendance rate.