Medication error is an event that can harm the patient so that it can endanger patient safety by health workers, especially in terms of patient treatment services. Medication errors can occur in every treatment process, one of which is in the prescribing phase. The occurrence of medication errors in the prescribing phase if the components such as the completeness of patient data, doctor data, and the date of the prescription are not completely 100% complete on the prescription sheet. treatment in pharmacies and healthy family clinics appeared. This study is a retrospective descriptive study. The data collection used a non-probability sampling technique with a total of 270 prescription samples taken from January to December 2020 at pharmacies and healthy family clinics. The results of the study indicate the potential incidence of medication errors in administrative completeness, including body weight 100%, gender 87%, doctor initials 83%, patient age 60%, doctor SIP 57%, prescription date 27%, doctor name 24%, and name 1% patients. Meanwhile, in pharmaceutical completeness, the potential incidence of medication errors includes incomplete strength of 77% of dosage forms, 28% of dosage forms. Incomplete prescriptions are still found in the writing of prescriptions that have the potential for medication errors to appear in pharmacies and healthy family clinics. The results of this study are expected to help improve the quality of service to patients and prevent medication errors in the prescribing phase.