A one-month-old boy, with type-II mucolipidosis, presented with congestive heart failure and elevated cardiac enzymes. The atretic nature of the orifice of the left coronary artery was revealed by retrograde flow on color Doppler and selective coronary angiography. Type-II mucolipidosis and atresia of the left coronary artery are rare. To the best of our knowledge, this is the first report of their combined occurence, suggesting a possible causal relationship.