The validated European Community Respiratory Health Survey questionnaire was used to conduct a field study on adults aged 20-65 years old in Khuzestan province, Iran. For this, the researchers used a two-stage cluster sampling method. Univariate and multiple logistic regression modeling were used to obtain odds ratio of potential risk factors. Results: The researchers handed out 5720 questionnaires of which 5708 were filled in. 231 cases of 478 individuals with asthma were male. The results showed that having airway hyper responsiveness (OR = 13.52; 95% CI: 9.61-19.02), having a family history of asthma (OR = 2.88; 95% CI: 2.23-3.71), residence in urban areas (OR = 2.15; 95% CI: 1.43-3.21), the presence of mildew in the building (OR = 1.95; 95% CI: 1.29-2.92) and the location of the house in the main street with respect to the auxiliary road (OR = 1.44; 95% CI: 1.14-1.82), respectively, were the most potent risk factors for asthma in adults. However, the presence of dense green space in the 200-m radius of the residential home (OR = 1.69; 95% CI: 1.30-2.20) and home gardening (OR = 1.42; 95% CI: 1.12-1.80) are the most important protection factors against asthma. Conclusions: This study showed the association between some environmental factors with the odds of having asthma. These factors can be considered in primary prevention programs for asthma.