The comprehensive assessment of patients with severe mental health problems includes the evaluation of needs, as this informs service planning, and levels of unmet need have been found to be associated with lower subjective quality of life. The Camberwell Assessment of Need is the most widely used instrument for this purpose. We report the development and evaluation of a new, patient-rated, short form (CANSAS-P). The CANSAS-P exhibited comparable detection of needs with its predecessor, better identification of domains that are problematic for patients to respond to, good test-retest reliability, especially for unmet needs, and generally positive evaluations by patients. We recommend the CANSAS-P as the needs assessment measure of choice for completion by patients.