ObjectiveTo investigate the daily antimicrobial use in patients at hospitals of different sizes in Guizhou province.MethodsAntimicrobial use in 108 hospitals on August 30， 2010 was investigated, all data were analyzed.ResultsA total of 29 358 inpatients were investigated, the usage rate of antimicrobial agents was 55.52%, 51.58% of which were for therapeutic purpose, 35.44% for prophylactic use, and 12.98% for both therapeutic and prophylactic application; 60.88% of patients received one agent， 35.80% received two, and 3.32% received three and more agents. Among patients who received antimicrobials for therapy， only 13.84% were sent specimens for pathogenic detection. The usage rates of antimicrobial agents were different among different hospitals， secondary hospital was 61.18%, and tertiary hospital was 47.35%(χ2=549.85，P＜0.05). Departments of pediatrics， respiratory diseases， and otolaryngology had higher antimicrobial usage rates, all were >75%. ConclusionInpatients in 108 hospitals have higher rate of daily antimicrobial use, prophylactic use and combined use, but pathogen detection rate is low. It is necessary to strengthen the management of rational use of antimicrobial use.