Acutely ill hospitalized older adults often experience a decline in function that may be preventable using a proactive, interdisciplinary, patient-centered approach. Hospitalists are treating an increasing number of these patients. A collaborative geriatrics consultation model to prevent functional decline and improve care for older patients with geriatrics syndromes was developed and implemented in partnership with a large hospitalist group in a community teaching hospital. A team of a geriatrician and a geriatrics nurse practitioner led the new consultation service. The team assisted with identifying cases, provided consultation early in the hospital stay, focused its evaluation on functional and psychosocial issues, and assisted in clinical management to optimize implementation of recommendations. In the first 4 years, the consultation service conducted 1,538 consultations in patients with a mean age of 81 (range 56-103). The most frequent geriatrics diagnoses were gait instability, delirium, and depression; recommendations usually included consulting physical therapy, increasing activity, and changing medications. The number of referrals and referring physicians grew steadily each year. Twenty-eight of 34 (82%) of the referring hospitalists completed a Web-based satisfaction questionnaire. All responding hospitalists agreed that proactive geriatrics consultation helped them provide better care; 96% rated the service as excellent. Analysis of hospital administrative data revealed a lower length of stay index and lower hospital costs in patients receiving a geriatrics consultation. The Proactive Geriatrics Consultation Service represents a promising model of collaboration between hospitalists and geriatricians for improving care of hospitalized older adults.