Background: Previous studies reported that the prevalence of drug allergy is higher in patients with cystic fibrosis (CF) than in the general population. It is important to exclude or confirm the drug allergy diagnosis with detailed allergic evaluation for preventing drug allergy overdiagnosis. Our study aims to determine the actual frequency of drug allergy proven by diagnostic tests in children with CF and to compare it with the control group. Methods: Patients diagnosed with CF who were followed up in the Pediatric Pulmonology Clinic were included in the study group. Children with similar gender and age characteristics who did not have any chronic diseases and who applied to the Pediatric Polyclinics were included in the control group. We reviewed the medical data of patients with CF. Also, we evaluated the parents of the patients via phone conversation and/or during the control of the outpatient clinic and questioned them in terms of drug allergy. In addition, we assessed those with suspected drug allergies in the pediatric allergy clinic for diagnostic tests and compared it to the control group. Results: CF patients (n = 44) and control group (n = 100) were included in the study. Only 1 patient (2.2%) out of the 44 patients in the study group had a suspicion of drug-related hypersensitivity history. In the control group, 1 patient had a history of rash, provocation test was performed to rule out drug hypersensitivity reaction, and it was evaluated as a negative result. Conclusions: The result of our study showed that the frequency of drug allergy in children diagnosed with CF was not different from the control group. However, it will be useful to confirm the data of pediatric patients with CF in larger groups. In the presence of suspicion of drug allergy, a diagnostic evaluation can prevent unnecessary drug allergy diagnoses.