The musculoskeletal (MS) involvement of 91 patients with bacterial endocarditis (BE) is reported. Twenty-three patients (25.2%) exhibited MS symptoms; 74% had arthralgias often associated with arthritis and low back pain (LBP), 48% had myalgias, and 43.4% had LBP. The articular symptoms usually were polyarticular and symmetric, affecting both the large and small joints. Two of 12 patients had a positive test for rheumatoid factor activity, and 2 of 5 had a positive FANA test. Patients with MS symptoms did not differ from those with no such symptoms by their mean age, by their underlying heart disease, or by the nature of their cardiac lesions. They were characterized by female preponderance and increased prevalence of streptococcal infections. In view of our data and the relevant literature, it seems that MS symptoms are common in patients with BE. They often antedate the diagnosis of BE by several weeks and can mimic other rheumatic diseases. Therefore, unexplained rheumatic symptoms should always alert the physician to the possibility of bacterial endocarditis.