Hospitalization may induce a decrease of muscle strength and muscle mass in older patients due to physical inactivity, malnutrition and diseases, negatively affecting health outcome. We aimed to examine the literature on change in muscle strength and muscle mass in older patients during hospitalization. A literature search was performed in major electronic databases from inception to March 2016. Studies including hospitalized patients with a mean age ≥ 65 years, describing change of hand grip strength and/or muscle mass were found eligible. Extracted data were divided in hand grip strength or muscle mass and stratified by elective or acute admission. Meta-analysis was conducted using Comprehensive Meta-analysis. Twenty-five studies were included, describing a total of 1789 patients with a mean age range of 65 to 85.8 years and an overall median length of stay of 14.7 days. Pooled hand grip strength and muscle mass were found to significantly decrease in electively admitted older patients during hospitalization (standardized mean difference (95% confidence interval): − 0.42 (− 0.66, − 0.17) and − 0.44 (− 0.61, − 0.27)), but not in acutely admitted older patients (standardized mean difference (95% confidence interval): 0.18 (− 0.02, 0.37) and − 0.25 (− 0.58, 0.09)). In conclusion, decrease in muscle strength and muscle mass in older patients is dependent on the type of admission.