The current study investigated the effectiveness of a group cognitive behavioral therapy for auditory verbal hallucinations (AVHs), the Voices Group. This consists of seven specific sessions. Forty-one participants with schizophrenic or schizoaffective disorders completed a battery of questionnaires. The severity of psychiatric symptoms, beliefs about voices, quality of life, self-esteem, clinical global impression, and functioning were assessed at baseline, before and after intervention, and at the 6-month follow-up. After intervention, there was a statistically significant reduction in the severity of AVHs. This result remained stable at follow-up. The dropout rate was high. Some differences were found in subjective experience of AVHs between the patients who completed the intervention and those who dropped out. Altogether, these findings suggest that a brief intervention has some positive benefits in patients struggling with voices, which remain stable over time.