Objectives Suitably qualified pharmacists in the UK are able to prescribe all medicines. While doctors' prescribing errors are well documented, there is little information on the rate and nature of pharmacists' prescribing errors. Our aim was to measure the prevalence of prescribing errors by pharmacists. Methods Prescribing by pharmacists, for inpatients admitted to three hospitals in North East England was studied. Part one measured the extent of prescribing by pharmacists as a proportion of all prescribing on a single day. The number of medication orders, reason for prescribing and therapeutic category were collected by the researcher (OC). In part two, pharmacist prescribing was reviewed for safety and accuracy by ward-based clinical pharmacists over 10 days; errors were documented and categorised as per EQUIP study. Results Part 1: Pharmacists prescribed one or more medication orders for 182 (39.8%) of 457 patients, accounting for 12.9% (680 from 5274) of all medication orders prescribed on a single census day. Pharmacists prescribed medicines from 12 out of 15 British National Formulary categories (no prescribing of drugs used in malignancy, immunology and anaesthetics). Part 2: 1415 pharmacist-prescribed medication orders were checked by clinical pharmacists, with four errors (0.3%) reported. Conclusions This study suggests that prescribing pharmacists can provide a valuable role in safely prescribing for a broad range of inpatients in UK general hospitals.