BackgroundScreening for mental disorders among prisoners is crucial for early detection and intervention of psychopathology and substance use disorders. In Italy, only a minority of prisons have implemented a structured screening process, and there is not yet a standard approach to this worldwide.AimsFirst, to describe a systematic psychological screening for early identification of mental disorder, including drug use disorders, and suicide risk among men on reception into one Italian prison, designed to inform management and, secondly, to describe mental health outcomes among those prisoners accepted into the in‐reach mental health service as a result of the assessment.MethodsAll prisoners newly received in the Parma Penitentiary Institute at any time in 2020 were screened using the Jail Screening Assessment Tool. Those who screened positive for any mental disorder, including substance use disorders and suicide indicators, were asked to complete the Parma Scale for the treatment evaluation of offenders with psychiatric disorders (Pr‐Scale), a locally developed tool that allows for the measurement of mental state change as well as changes in treatment and management. Scores on this scale soon after reception were compared with scores after 1 year of work with the in‐reach team.ResultsAmong 303 newly admitted male prisoners in 2020, 167 (55%) screened positive for substance use disorder and 30 (10%) for other primary mental disorders. Most of these (n = 151) were offered and accepted care by the mental health in‐reach service. After 1 year, those who had been treated by this service showed significant improvement in all Pr‐Scale clinical variables.ConclusionsOur findings support the extension of a psychological screening into a service for new receptions to Italian prisons. They add evidence for the utility of the Pr‐Scale for detecting those newly admitted prisoners likely to benefit from early mental health interventions provided by in‐reach services and for evidencing resultant change. Future studies are needed to replicate our results in other Italian prisons as a precursor to systems improvement, while other countries might also benefit from using similar evaluation and reevaluation routinely.