Background: Tetralogy of Fallot is usually diagnosed while the baby is a child or soon after. Occasionally, depending on the inflexibility of the symptoms, tetralogy of fallot isn't detected until adulthood. All infants who have tetralogy of fallot need repair or surgery. Infants with tetralogy of fallot need regular doctor's checks for the remaining life and may have some restrictions. Methods: We present a case 14 year old female patient name XXX was admitted to the cardiology ward, with the chief complaints of palpitation, shortness of breath, intermittent chest discomfort, unable to sleep on the left side, unable to move during sleep, dyspnea on exertion for 5 days. She was not on any past medication but she had been using OTC medications from childhood whenever she feels pain and it will be reduced by taking rest for 10-20 mins, the patient was alright now she can do all her activities without other's support, but unable to move during sleep and unable to sleep on the left side from past 5 days. Results: Her lab investigations were echo cardiogram report showed right ventricular hypertrophy, over-ridding of the aorta, pulmonary stenosis, bidirectional shunt, and ventricular shunt, and she was diagnosed as teratology of fallot. Conclusion: Tetralogy of fallot is a condition that is primarily present in infants it should be carefully observed and diagnosed at earlier ages.