Sixteen patients with serologically proven Q-fever infection are reviewed. Fifteen had significantly raised antibody titres to both phase I and phase II Coxiella burneti antigens, indicating persistent or chronic infection. One patient, a premature infant who died, had raised phase II titres only, but is included together with the mother who had chronic Q-fever and was the presumed source of infection. Chronic Q-fever infection has previously been regarded as virtually synonymous with Q-fever endocarditis, but only seven of the patients in this survey had evidence of valvular endocarditis. In those who did, the infection had arisen on prosthetic valves or those affected by rheumatic or syphilitic heart disease. One patient had inexorably progressive destruction of an infected congenitally bicuspid aortic valve. Eight patients had infections associated with extra-valvular sites and several of these associations have not been previously described. These include extreme prematurity with perinatal death, possibly following transplacental infection, the sudden infant death syndrome (SIDS), multiple lower limb emboli from endocarditis of an abdominal aortic dacron graft, and colonization of ventricular endocardium following left ventricular myotomy/sub-aortic diaphragm resection. The current concept that chronic Q-fever is invariably associated with endocarditis is therefore untenable and the indications for phase I antibody screening should be extended to include patients other than those under investigation for 'culture-negative' endocarditis, for example those with unusual osteomyelitis of vertebrae.