Two patients, both women, one with "lupus-like" disease, age 51 years, the other a 45-year-old with systemic lupus erythematosus (SLE), developed symptoms and echocardiographic signs of hypertrophic cardiomyopathy. One patient had a family history of sudden maternal death. Neither patient had a history of sustained hypertension and there were no significant valvular lesions detectable to account for the septal and ventricular hypertrophy. The association of SLE or any related condition with hypertrophic cardiomyopathy has not been recorded. In one patient the question of a hereditary cardiomyopathy remains a possibility. The diagnosis of the condition was based on clinical and echocardiographic grounds alone. No endomyocardial biopsies were performed.