Introduction: Bladder cancer is regarded as the most common urinary malignancy in the world. As other cancers, its incidence has increased in recent years. Hence, the present study was conducted to investigate the relationship between smoking and opium and bladder cancer in residents of Yazd province.

Materials and Methods: This case-control study was performed on 200 patients with bladder cancer and 200 matched healthy individuals in Yazd province. Research data was gathered through interview and administration of a researcher-made questionnaire.  Furthermore, chi-square and regression tests were carried out with SPSS software (version 18).

Results: The mean and standard deviation of age in case and control groups were reported to be 61.54 ± 13.61 and 61.45 ± 13.3 respectively. Education level, type of oil consumed, weekly frequency of smoking and fried foods, white meat, red meat consumption involve the predictive factors for bladder cancer; as consumption of hydrogenated fats, animal fats, fried foods more than 4 times per week and red meat had (OR=1.31;95% CL,0.63-2.71), (OR= 6.32;95% CL,2.03-19.8), (OR=2.86;95% CL,1.2-6.8) and (OR=51.18;95% CL,14.78-177.03) times greater risk for bladder cancer respectively and also low education level. White meat intake had a protective effect. Moreover, in line with increasing number of cigarettes per day, the risk of bladder cancer increased.

Conclusion: The findings of the present study revealed that smoking and opium are risk factors of bladder cancer. Thus, appropriate training and intervention program need to be taken into account in order to prevent the cancer.