Discrepancies between drug stock recorded in the Hospital Management Information System (SIMRS) and physical stock can reduce the efficiency of pharmaceutical services and threaten patient safety. This study aimed to describe drug stock discrepancies at the Pharmacy Warehouse of Andalas University Hospital, together with the condition of four related factors: human resources (HR), standard operating procedures (SOP), SIMRS, and drug management. A descriptive quantitative design was applied from April to May 2026. Stock data for 84 drug items were compared between SIMRS records and physical counts, and 34 pharmacy staff completed a Likert-scale questionnaire. Data were analyzed univariately. Of the 84 items, 65 (77.4%) showed no discrepancy, whereas 19 (22.6%) did. Most respondents rated HR (52.9%), SOP (58.8%), and drug management (52.9%) as poor, while 52.9% rated SIMRS as good. These findings show that stock discrepancies persist alongside weaknesses in staff thoroughness, SOP compliance, and stock recording, even though SIMRS itself was considered adequate. Strengthening staff competence, SOP supervision, real-time data entry, and the recording of every drug transaction is needed to reduce stock discrepancies