Polypharmacy, which refers to the situation of a patient taking more medications than is clinically necessary, has become a major problem in recent years. Although the effects of medications on pressure ulcers have been reported, there are no reports on the impact of the total number of medications on pressure ulcers. The purpose of this study was to investigate the effect of number of medications on the severity of pressure ulcers. Participants included 94 patients who were admitted to Chiba University Hospital with pressure ulcers between April 2013 and March 2021. Univariate analysis identified ulcer depth, weight loss and anticoagulant use to be factors that contributed to the severity of pressure ulcers. Multiple regression analysis was performed for six variables, namely, the number of medications, ulcer depth, weight loss and anticoagulant use, as well as diabetes status and total serum protein level, which have been reported to be associated with pressure ulcers in previous studies. The following independent risk factors were identified: weight loss (β 0.207, 95% confidence interval [CI] 0.700-3.193; p = 0.003), anticoagulant use (β 0.161, 95% CI 0.271-3.088; p = 0.020) and ulcer depth (β 0.719, 95% CI 7.172-10.329; p < 0.001). The number of medications was not a significant factor. This study revealed that the number of medications a patient is taking does not affect the severity of pressure ulcers. The findings should provide useful information for the management of pressure ulcers.