Background: Cystic Fibrosis (CF), affecting functional exercise capacity generally measured by submaximal exercise test such as 6min walk test, is a progressive, autosomal recessive and metabolic disorder. Three-axis accelerometers, which are used during gait, are an easy way to assess gait parameters in patients and healthy individuals. Gait parameters were significantly associated with clinical outcomes of COPD. However, the association between gait parameters and clinical outcomes in children with CF is unclear. Research question: Do clinical outcomes in CF have an important role in determining gait parameters?. Methods: Twenty-one CF and 21 healthy subjects participated in this case-control study. Body composition was evaluated using Tanita-BC 418. Respiratory and knee extension muscle strengths were assessed. Functional exercise capacity was evaluated using the 6-min walk test (6MWT). Spatiotemporal gait parameters were evaluated using a validated wireless inertial sensing device (G-Sensor, BTS Bioengineering S.p.A., Italy) during the 6MWT and 7-meter gait test. Results: MIP, the distance of 6MWT, and stride length were significantly lower in the CF group compare to healthy children (p<0.05). Gait speed and functional exercise capacity, cadence and functional exercise capacity, quadriceps muscle strength, FEV1, fat-free mass were found to be correlated in CF patients (p<0.05). Significance: The aerobic capacity and gait parameters were affected in CF patients with mild disease severity in our study. Clinical outcomes were associated with gait parameters in CF patients. This is the first study to use the 3-axis accelerometer to evaluate functional exercise capacity and gait parameters of CF and healthy children. A three-axis accelerometer can be used to assess functional exercise capacity and gait parameters in CF patients at the clinics.