Background: Cystic fibrosis (CF) is a common genetic disorder chiefly characterized by respiratory and gastrointestinal symptoms. The purpose of this study was to evaluate the clinical presentation and growth status in CF patients at the time of diagnosis and following conventional treatment.Materials and Methods: A cross-sectional study was conducted on 67 CF patients who enrolled for at least a two-year follow up period in the CF Clinic of Sarvar Pediatric Hospital. Disease diagnosis was based on a positive sweat test. Growth indicators and initial clinical presentations of patients were registered at the time of diagnosis. Weight and height was measured at each clinical visit during follow up. All patients were treated with enzyme replacement, vitamin and mineral supplements. Other medications were prescribed as clinically indicated. Statistical analyses were performed by SPSS 16.0 for MS Windows.Results: The mean age of patients was 24.9±37.7 months at the time of diagnosis, whereas it was 3.1±2.1 months at the onset of CF symptoms. At diagnosis, the majority of CF patients suffered from malnutrition, growth failure, and presented with pulmonary and gastrointestinal symptoms. After conventional and nutritional treatments, significant improvements were seen in weight and height.Conclusion: A delay in the diagnosis of CF as seen in our country causes patients to further suffer from malnutrition and growth failure in comparison to developed countries. This emphasizes the necessity of neonatal screening. The results of this study show the dramatic effects of nutritional treatment on growth status.