Objectives: The objective of this study was to describe the prevalence of osteosarcopenia and its association with falls, fractures, and mortality in community-dwelling older adults. Design: Follow-up of ALEXANDROS cohorts designed to study disability associated with obesity in older adults. Setting and Participants: Community-dwelling people aged 60 years and older living in Chile. Measures: At baseline, 1119 of 2372 participants had a dual-energy X-ray absorptiometry scan and the measurements for the diagnosis of sarcopenia. World Health Organization standards for bone mineral density were used to classify them as normal, osteopenia, and osteoporosis. Sarcopenia was identified using the algorithm from the European Working Group on Sarcopenia in Older People 1, validated for the Chilean population. Osteosarcopenia was defined as having sarcopenia plus osteoporosis or osteopenia. Results: The sample of 1119 participants (68.5% female) had a mean age of 72 years. At baseline, osteoporosis was identified in 23.2%, osteopenia in 49.8%, sarcopenia in 19.5%, and osteosarcopenia in 16.4% of the sample. The prevalence of osteosarcopenia increases with age, reaching 33.7% for those older than 80 years. Sarcopenia was found in 34.4% of osteoporotic people and osteoporosis in 40.8% of those with sarcopenia. After 5640 person-years of follow-up, 86 people died. The mortality was significantly higher for the group with osteosarcopenia (15.9%) compared with those without the condition (6.1%). After an adjusted Cox Regression analysis, the hazard ratio for death in people with osteosarcopenia was 2.48. Falls, fractures, and functional impairment were significantly more frequent in osteosarcopenic patients. Conclusions and Implications: Osteosarcopenia is a common condition among older adults and is associated with an increased risk of falls, fractures, functional impairment, and mortality. Considering the high proportion of sarcopenia among osteoporotic patients and vice versa, screening for the second condition when the first is suspected should be advised.