Carnitine Acylcarnitine Translocase (CACT) deficiency and Carnitine Palmitoyl Transferase (CPT I and II) deficiency comes under a group of disorders called mitochondrial fatty acid oxidation disorders, due to defects in the carnitine cycle. The CPT and CACT enzymes play a pivotal role in the transfer of Long Chain Fatty Acids (LCFA) from the cytoplasm to the mitochondrial matrix, where β-oxidation take place. In the present case, a male baby presented on day 2 of life with chief complaints of respiratory distress, apnoea, lethargy and seizures. The baby had multiple episodes of hypoglycaemia and seizures after admission. Diagnosis was made with the help of extended newborn screening using Tandem Mass Spectrometry (TMS) showing accumulation of hexadecanoyl carnitine due to CACT/CPT II deficiency. Echocardiography showed features of cardiomyopathy with cardiomegaly. Liver Function Test (LFT) and Prothrombin Time-International Normalisation Ratio (PT-INR) of the child was also deranged, with hypotonia of all muscles. Early detection along with carnitine supplementation and further prevention of fasting episodes resulted in generalised improvement of the baby. So, a high degree of suspicion of Inborn Error of Metabolism (IEM) and timely diagnosis can save the baby