Evidence-based practices for forensic mental health services have been slow to develop, and there is a lack of measures that assess the mental health and criminogenic needs of people experiencing mental illness who have offended. The present study aimed to investigate the interrelationship between a clinician-rated forensic mental health needs assessment (Health of the Nation Outcomes Scales-Secure (HoNOS-S)), a forensic mental health needs assessment that considers both clinician and patient perspectives (Camberwell Assessment of Need-Forensic (CANFOR)), and measures of general and violent recidivism (Level Service-Case Management Inventory (LS-CMI) and HCR-20 Violence Risk Assessment Scheme (HCR-20)). Needs were assessed for 72 forensic patients aged between 20 and 62years of age, located in a secure forensic mental health facility. The findings revealed significant positive correlations between the HoNOS-S, CANFOR, and HCR-20. Only the CANFOR was positively correlated with the LS-CMI, and uniquely contributed variance to the HCR-20. Patients and nurses differed in the total number of needs and met needs they identified as present. The findings suggest that the collaborative approach of the CANFOR might be more appropriate for measuring outcomes in the treatment of individuals experiencing mental illness who have offended.