The aim of this study was to investigate the reliability, validity and structure of the Psychotic Symptom Rating Scales (PSYRATS) in 257 subjects presenting with acute first episodes of schizophrenia or related disorders. The PSYRATS have been shown to assess dimensions of hallucination and delusions reliably and validly in chronically psychotic patients but not in first episode patients. Item reliability was investigated and subscale performance compared to the PANSS. The PSYRATS had good inter-rater and retest reliability. Validity was good, as assessed by internal consistency, sensitivity to change, and in relation to the PANSS. There was evidence of two delusion factors and three for hallucinations. The scales are useful complements to existing measures of symptom severity. © 2006 Elsevier B.V. All rights reserved.