Background <p>Sarcopenia is a major public health problem. The main aim of this secondary data study was to assess the prevalence, determinants and risk factors of sarcopenia among middle-aged adults, from metropolitan cities using the SWAG-SARCO, 2021 criteria. Dataset of Longitudinal Ageing Study in India (LASI) Wave 1 (2017–2018) was used.</p> Study design <p>A secondary data analysis of the LASI Wave 1 (2017–2018) dataset (data of population living in metropolitan cities was sifted from the national dataset).</p> Methods <p>2227 urban adult men and women aged 40–59 years, living in metropolitan cities (Kolkata, Mumbai, Delhi and Chennai) of India were included in this study. Prevalence of sarcopenia was assessed using the SWAG-SARCO diagnostic criteria (impairment in any two of the following components: muscle strength, muscle mass, and physical function). Mean was compared using one way ANOVA. To identify determinants and risk factors multinomial logistic regression was used.</p> Results <p>As per SWAG SARCO criteria prevalence of sarcopenia was found to be 18.14% among middle-aged urban adults; higher among women than men. 43.15% were at-risk of sarcopenia. The mean appendicular skeletal mass index, timed walk, and grip strength were significantly different (<i>p</i> &lt; 0.05) across sarcopenic, at-risk, and non-sarcopenic groups. Female gender, age, region, monthly per capita consumption expenditure quartile, working status were the salient determinants significantly associated with occurrence of sarcopenia. Risk factors such as lower body mass index (BMI), height, hip circumference and higher waist circumference were significantly associated with sarcopenia.</p> Conclusions <p>Results indicate need for developing policies and programmes aimed at early screening, prevention, management and treatment of sarcopenia.</p>