Objectives: Osteoporosis is one of the health issues caused by smoking. Osteoporosis is the most commonly seen bone disease and becoming a major public health issue due to extension of lifetime. Studies on detection of smoking related osteoporosis in males are limited in our country. Therefore we intended to assess the effects of smoking on bone mineral density in middle aged male patients alongside of related factors. Methods: Our study is a case control type analytical research. We included 144 male smoker patients, aged between 30-60 years-old, and 100 male volunteers, never smoked. Bone mineral density (BMD) of the patients' lumbar spine (L1-3 and L2-4) and proximal femur (femur total, femur trochanter and wards triangle) regions of the individuals were measured anteroposteriorly by using dual energy x-ray absorptiometer (DXA) method. Serum Ca, P, ALP, PTH and total vitamin D levels of the samples were studied. Results: The means of L1-L4 lumbar spine bone mineral density, femoral neck bone mineral density, femoral trochanter bone mineral density and total femoral bone mineral density were significantly lower in the case group than the control group, according to DXA measurements (p=0.017, p=0.047, p=0.005 and p=0.009; respectively). There was a slightly strong correlation and a negative statistically significant difference between femoral trochanter BMD and both cigarette consumption (per-day) and packets-year (r=-0.153, p=0.017 and r=-0.142, p=0.027; respectively). The mean levels of serum calcium were significantly higher in the case group than the control group (p=0.018). Conclusion: We can conclude that smoking has decreasing effects on bone mineral density.