Background: Outcomesforcystic fibrosis PATIENTS are improving rapidly. The demographic factors are notable variables inoutcomes, which can be evaluated and modified.Objectives: This study was designed to investigate the association between outcome and demographic factors in PATIENTS with cystic fibrosis.PATIENTS and Methods: This was a cross-sectional study and data were gathered for 331 PATIENTS using the census method, from March 2001 to September 2014 in Iran. Data was analyzed using logistic regression analysis, chi-square test, and independent sample t test using SPSS 18. Odds ratio with confidence intervals of 95% and P<0.05 were considered significant.Results: There were 85 (25.7%) deceased PATIENTS and 246 (74.3%) living PATIENTS at the time of the study. Of the 246 living CF PATIENTS, 202 (82.2%) were less than nine years of age, and 77 (90.6%) out of the 85 deceased CF PATIENTS had died younger than four years of age. There was a significant difference between outcome and location of residence. The risk of mortality was 50% less in urban PATIENTS than in rural PATIENTS (P=0.03). The risk of mortality was approximately two times higher in PATIENTS with a positive family history than in those with a negative family history (P=0.02). The proportion of mortality was approximately two times, or 94%, higher for those in a consanguineous marriage than for those in a non-consanguineous marriage (P=0.01).Conclusions: The results demonstrated that the mortality rate was higher in CF PATIENTS with a positive family history, a consanguineous marriage, and residence in a rural area. Therefore, demographic factors play an important role in the outcome of cystic fibrosis. Unfortunately, these parameters, which can be managed easily and with low cost, have been overlooked.