Noncommunicable chronic diseases among the elderly population represent a significant economic burden in China. However, previous disease-related health cost studies lacked representation of older adults and comparability of the burden of multiple chronic diseases. The objective of this study was to determine the fraction of health care costs attributable to the 6 most prevalent chronic diseases and comorbidities in the sample of older adults. This study employed data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), with 3 waves in 2011, 2014, and 2018, and included 18 349 observations in total. Outpatient costs, inpatient costs, and total health care costs were included in this study. Based on a 2-part random effects model, the effect of chronic disease on health service utilization was first explored by constructing a dummy variable for whether or not to utilize health care, followed by estimation of attributable costs in the population with health care utilization. Among the older adults in the sample, hypertension, heart disease, cataracts, arthritis, stroke or Cerebrovascular disease (CVD) and chronic lung disease are the 6 most prevalent chronic conditions. The costs attributable to the 6 chronic diseases mentioned above were 36.00% of outpatient costs, 55.92% of inpatient costs, and 45.05% of total health care costs for older adults. Of these, heart disease, stroke or CVD, and chronic lung disease accounted for 22.11%, 13.24%, and 10.56% of total health care costs, respectively. Moreover, the proportion of health care costs attributable to chronic diseases was higher for older adults who were male, lived in urban areas, and had a lower level of education. The proportion of health care costs attributable to chronic diseases is substantial among older adults in China. Health care costs associated with chronic diseases can be decreased with well-targeted interventions and comprehensive access to health services.