Prescribing errors (PEs) can lead to patient harm. Prediction tools are available to detect patients at risk but are not ideal. We investigated whether doctors can identify hospitalized patients at risk of medication-related harm by assessing the prevalence of PEs. This matched case-control study was carried out on three clinical wards (Internal Medicine, Upper GI Surgery, and Otolaryngology & Oncology) in an academic hospital in the Netherlands. A total of 387 patients with 5191 prescriptions were included. A multidisciplinary in-hospital pharmacotherapeutic stewardship team detected 799 PEs affecting 279 patients (72.1%). Most (58.8%) PEs occurred during hospitalization. Doctors identified 40 patients (cases) as needing a clinical medication review (CMR). These patients were matched by age (10 years) and the number of prescriptions at the time of CMR (1), 1:1 with patients not selected for CMRs (controls). There were no significant differences in age, number of prescriptions, sex, renal function, or documented allergies or intolerances between the matched cases and controls or between controls and other patients who did not received a CMR. The incidence of PEs was higher among cases than controls, and more cases than controls had one or more PEs (97.5% versus 72.5% (OR=14.8, 95% CI [1.8 – 121.1], p=0.002)). The rate of PEs was three times higher in cases than in controls (IRR=3.0, 95% [2.3 – 4.0], p<0.001). In conclusion, clinical ward doctors can effectively identify patients with PEs thus at risk of medication-related harm. This may be a new and interesting selecting strategy for targeted PE-mitigating interventions.