The authors used the National Ambulatory Medical Care Survey: 1999 Summary to compare the practice patterns of osteopathic and allopathic physicians in the management of musculoskeletal disorders in family practice settings. Patient and physician characteristics, diagnostic test ordering patterns, treatments, and amount of time spent with patients during visits were compared. Patients who visited osteopathic physicians were more likely to be middle-aged and referred, with injury-related visits that were self-paid. Osteopathic physicians spent more time with patients, ordered a greater number of nontraditional diagnostic tests, and provided more manual and complementary modes of therapy. In contrast, although most of the patients seen by both osteopathic and allopathic physicians were white, allopathic physicians had a greater percentage of patients who were of an ethnic minority or under Medicaid or Medicare. Allopathic physicians ordered a greater number of traditional diagnostic tests and prescribed more medications. Based on the nationally representative data, osteopathic physicians used physiotherapy (including osteopathic manipulative treatment and physical modes of therapy) and complementary treatments to a greater degree in their physician-patient contacts. In contrast, allopathic physicians spent more resources on diagnosis versus treatment (eg, physiotherapy) and seemed to focus on the search for a nonstructural medical cause.