Background: smoking is considered as a major risk factor of bone fractures. This is attributed to decrease of serum calcium in smokers. Smokers are vulnerable to bone fractures more than non-smokers. Aim of the study: the study aims to assess the effect of smoking on patients involved with bone fractures. Patients and methods: the study was composed of 204 patients (smokers and nonsmokers). 78 smokers with bone fractures and 51 nonsmokers with bone fractures were interpreted. They were imaged with x-rays to diagnose the fractures. Biochemical procedure and measurements were performed to estimate serum calcium and alkaline phosphatase. Results: serum calcium is significantly decrease in fractured-bone smokers more than nonsmokers (p-value = 0.012), alkaline serum is significantly increased in smokers more than nonsmokers (p-value = 0.041). There was strong negative correlation between the levels of serum calcium and the number of cigarettes smoked per day (P-value = 0.016, R = 0.443). A strong negative correlation existed between the levels of serum calcium and the duration of smoking per years (P-value = 0.01, R = 0.42). A moderate positive correlation between the levels of serum calcium and the number of cigarettes smoked per day (P-value = 0.042, R = 0.277). Conclusion: smoking is an increased relative risk factor of bone fractures in Sudanese cigarette smokers. Bones of smokers were vulnerable to fractures more than non-smokers.