BACKGROUND:: Osteoporosis is a multifactorial disease which is regulated by genetic and environmental factors. Polymorphism of the vitamin D receptor (VDR) gene has been reported to play a major role in variations for genetic regulation of bone mass, but its role within various ethnic populations is controversial. OBJECTIVE:: To investigate the association between VDR genetypes of Fok I polymorphism and bone mineral density, so as to explore the genetic susceptibility for osteoporosis in male from Beijing. DESIGN, TIME AND SETTING:: The randomized controlled observation was performed at Department of Endocrine at the Second Artillery General Hospital of Chinese PLA and Laboratory of Molecular Biology, Institute of Geriatrics and Gerontology, General Hospital of Chinese PLA between September 2004 and December 2007. PARTICIPANTS:: A total of 230 healthy male from Han nationality who dwelled in Beijing, aged 20-80 years, were selected from September 2004 to December 2006. METHODS:: The genotypes of VDR gene Fok I polymorphism were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method. Bone mineral density values were determined on random chosen 100 subjects by dual energy X-ray absorptiometry at lumbar vertebra and hip. MAIN OUTCOME MEASURES:: ①The subjectsʼ age, height and body weight. ②The genotypes of VDR gene Fok I polymorphism. ③Bone mineral density values at lumbar spine (L2-4), femoral neck, trochanter and Wards triangle. RESULTS:: The genetypes and gene frequency distribution of VDR gene Fok I polymorphism was FF 36.96%, Ff 46.96%, ff 16.08%, in accordance with Hardy-Weinberg equilibrium. After adjusting for age, height, body weight and body mass index, the bone mineral density in the men with ff genetype was lower than with Ff and FF genetypes (P = 0.037). There was a trend of ff genetype with lower bone mineral density at other sites, but no significant differences in other groups (P > 0.05). CONCLUSION:: There is a possible correlation between CDR gene Fok I polymorphisms and bone mineral density in Han male of Beijing. It can be employed to screen the high risk population of osteoporosis in men.