We investigated the association between familial Mediterranean fever (FMF) and osteoporosis (OP) in adult patients. Thirty-five attack-free FMF patients (28 females, 7 males; mean age 36.9 +/- 5.7 years) were individually matched to control subjects on the basis of age (within 2 years) and sex. All patients were taking regular colchicine. Subjects having any condition that can cause decreased bone mineral density (BMD) were excluded from the study. BMD was measured at the spine and femur by dual X-ray absorptiometry (DXA). Data was given as the median (IQR). T scores of the spine were -0.700 (-1.097 to -0.262) and -0.450 (-0.830 to 0.112) in FMF patients and healthy controls, respectively (p > 0.05). T scores of the femur neck were -0.900 (-1.480 to -0.570) and -0.430 (-1.472 to 0.247) in FMF patients and healthy controls, respectively (p > 0.05). Total femur T scores were significantly lower in FMF patients than healthy controls (-0.780 [-1.222 to -0.085] vs. -0.100 [-0.765 to 0.537], respectively, p = 0.021). Total femur T scores were significantly decreased in adult patients with FMF. Ongoing subclinical inflammation may be associated with decreased bone mineral content in those patients.