Antibiotics are a class of drugs that are widely used to eliminate the causes of many infectious diseases around the world. It should be borne in mind that their irrational and irregular administration will increase bacterial resistance and dangerous complications. For this reason, timely diagnosis and usage of antibiotics is one of the tasks of physicians to improve the patient's use of the lowest number of antibiotics. This was a retrospective descriptive cross-sectional study. The samples were selected by non-random sampling from all records of patients admitted to Shahid Sadoughi Hospital of Yazd from HIS hospital system with total number of 82742. The type of hospital admission, the type of prescription, the cause of antibiotic prescription, the cost of antibiotic use was entered into the questionnaire. The most commonly used antibiotics were cefazolin with a frequency of 18.41%, clindamycin with a frequency of 17.49%, ceftriaxone with a frequency of 15.48% and vancomycin with a frequency of 10.18% and metronidazole with a frequency of 7%, respectively. The most costly antibiotics were meropenem (14.28% of costs), vancomycin (13.4%), and amphotericin (10.09%). The pattern of antibiotic use in hospitals should be more carefully considered and given the cost and burden of unnecessary antibiotic use, serious consideration should be given to antibiotic use.