Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Heart failure (HF) in a case of uncomplicated TOF is uncommon but can occur under special circumstances. TOF associated with hypertrophic obstructive cardiomyopathy (HOCM) is a very rare combination of anomalies, and very few cases have been reported in the literature. Here, we report the case of a 2-month-old male infant who presented to us with central cyanosis and features of HF. He was worked up and found to have TOF with HOCM and advised surgical correction. Hence, we propose that HOCM is also one factor which can precipitate HF in a patient of TOF along with the classical causes mentioned in the literature. Furthermore, the left ventricular outflow tract obstruction of HOCM in a patient of TOF has an inverse relation with the degree of cyanosis.