Inborn Errors of Metabolism (IEM) are rare congenital diseases. It arises due to a defect of single genes that code for enzymes that helps to convert substrates into their products by participating in certain metabolic pathway. IEM affects every organ, from the fetus to geriatric life. Majority of IEM are inherited in an autosomal recessive manner. The frequency for each individual disease is decided by the geographical and ethnic composition of the population. The incidence of IEM varies from community to ethnicity to religion to location. Any patient with unexplained neurological condition should be considered for an underlying IEM. Newer scientific technologies have to be converted into diagnostic and therapeutic use which can offer enormous benefit to patients suffering from IEM, and preventing life-long burden and suffering. The overall aim should be to diagnose IEM early in life in order to prevent neurological damage and loss of life.