Aim Older adults often present with several comorbidities, including sarcopenia. However, the prevalence of sarcopenia and its associations with other comorbidities in hospitalized older adults are unknown. The present study aimed to determine the prevalence of sarcopenia, and its associations with other comorbidities in hospitalized older adults. Methods The present cross‐sectional study included 619 patients admitted to a geriatric hospital. The prevalence of comorbidities in the presence and absence of sarcopenia, nutritional status (according to body mass index and the Mini‐Nutritional Assessment‐Short Form), and activities of daily living (according to the Barthel Index) were assessed. Sarcopenia was defined as skeletal muscle loss evaluated by both bioelectrical impedance and handgrip strength analyses. Results Of the 619 participants (mean age 83.0 ± 8.2 years), 417 (67.4%) and 87 (14.1%) had definitive and possible sarcopenia, respectively. The prevalence rates of cognitive impairment and stroke were significantly higher in patients with definitive sarcopenia and those with possible sarcopenia than in those without sarcopenia (cognitive impairment 54.4%, 70.1% and 20.9%, respectively, P < 0.001; stroke 31.2%, 48.3% and 19.1%, respectively, P < 0.001). Multivariate logistic regression analysis showed that cognitive impairment was independently associated with sarcopenia after adjusting for age, sex, the Mini‐Nutritional Assessment‐Short Form score, Barthel Index and primary disease (adjusted odds ratio 1.98, 95% confidence interval 1.06–3.71; P = 0.032). Conclusions Sarcopenia might be highly prevalent among hospitalized older adults. Furthermore, cognitive impairment might be an independent explanatory variable of sarcopenia. Therefore, further studies on sarcopenia in patients with cognitive impairment are warranted.