Background <p>Cardiometabolic multimorbidity (CMM) has become a significant public health challenge in the context of global ageing. Sleep disorders are prevalent in older adults with CMM, but their correlations with physical activity and a body shape index (ABSI) remain unclear. This study aimed to investigate the independent and joint associations of physical activity and ABSI with sleep disorders in older adults with CMM.</p> Methods <p>This cross-sectional study was conducted between February and March 2024 and recruited 650 older CMM patients (aged ≥ 65 years) by random sampling. Data were collected using a structured questionnaire as well as the Pittsburgh Sleep Quality Index (PSQI) and the International Physical Activity Questionnaire-short form (IPAQ-SF). Logistic regression models were used to assess the independent and joint associations of physical activity and ABSI with sleep disorders.</p> Results <p>The prevalence of sleep disorders among older CMM patients was 48.46%, and low IPAQ (OR = 3.61, 95%CI: 2.41 to 5.43) and high ABSI (OR = 1.46, 95%CI: 1.04 to 2.04) were identified as independent risk factors for sleep disorders. The risk of sleep disorders in patients with low IPAQ and high ABSI group was approximately 5.1 times higher than that in patients with middle/high IPAQ and low ABSI group (OR = 5.10, 95% CI: 2.88 to 9.02). The stratified analyses indicated that these relationships were particularly pronounced in the &gt; 70 years and female subgroups.</p> Conclusion <p>This study highlights the important impact of physical activity and body shape management on sleep disorders in older CMM patients.</p>