PurposeTo determine the nature and frequency of medication errors during medication delivery processes in a public teaching hospital geriatric ward in Bali, Indonesia.MethodsA 20-week prospective study on medication errors occurring during the medication delivery process was conducted in a geriatric ward in a public teaching hospital in Bali, Indonesia. Participants selected were inpatients aged more than 60 years. Patients were excluded if they had a malignancy, were undergoing surgery, or receiving chemotherapy treatment. The occurrence of medication errors in prescribing, transcribing, dispensing, and administration were detected by the investigator providing in-hospital clinical pharmacy services.ResultsSeven hundred and seventy drug orders and 7,662 drug doses were reviewed as part of the study. There were 1,563 medication errors detected among the 7,662 drug doses reviewed, representing an error rate of 20.4%. Administration errors were the most frequent medication errors identified (59%), followed by transcription errors (15%), dispensing errors (14%), and prescribing errors (7%). Errors in documentation were the most common form of administration errors. Of these errors, 2.4% were classified as potentially serious and 10.3% as potentially significant.ConclusionMedication errors occurred in every stage of the medication delivery process, with administration errors being the most frequent. The majority of errors identified in the administration stage were related to documentation. Provision of in-hospital clinical pharmacy services could potentially play a significant role in detecting and preventing medication errors.