Background: Cystic fibrosis (CF) is a chronic autosomal recessive disease caused by CF transmembrane conductance regulator (CFTR) gene mutations, which encodes the CFTR protein. Impaired function of this protein leads to increased mucus thickness with subsequent chronic infections. The fungal biota in CF is dominated by Aspergillus and Candida species (spp). Aim of the Work: To determine the common lower respiratory tract infections among CF pediatric patients and to correlate culture results with the patient clinical status. Patients and Methods: A Cross Sectional Study was applied on 32 lower respiratory samples collected from CF pediatric patients admitted to Chest department, Pediatric Hospital, Ain Shams University. Samples were tested through bacterial and fungal culture. Results: Bacterial growth was detected in five samples (15.6%), where Pseudomonas spp was the most common bacteria, Fungal growth was detected in three samples (9.4%), all showed growth of Candida spp. Two samples showed mixed growth of Pseudomonas spp and Candida non albicans. Conclusion: Pseudomonas spp was the most frequent pathogen isolated from CF patients. Candida spp was the predominant fungal species detected.