Congenitally corrected transposition of the great arteries (CCTGA) is a rare congenital heart disease (CHD). In majority cases CCTGA is accompanied by other concomitant CHD. The isolated form is detected in approximately 1 % from the general amount of patients with this pathology. Diagnosis of CCTGA without other concomitant CHD appears very rarely in the clinical practice. The isolated form of CCTGA may have the protracted asymptomatic period that diminishes probability of its timely diagnosis. For patients with CCTGA low exercise tolerance is often detected even during asymptomatic period. In literature solitary clinical cases of high exercise tolerance in patients with CCTGA were described. The article dwells attention of the general cardiologists to clinical course of the disease and presents case of the first diagnosed isolated form of CCTGA in 21 years old young man with the high exercise tolerance.