Many inborn errors of metabolism can be completely cured with early detection and early treatment. This is why neonatal screening on inborn errors of metabolism is implemented worldwide. In 1991, the Ministry of Health & Social affairs adopted a nationwide service program for neonatal screening of phenylketonuria, galactosemia, maple syrup urine disease, homocystinuria, histidinemia and congenital hypothyroidism for newborns delivered from low class pregnant women registered in health centers. Government decreased the test items from six to two, PKU and congenital hypothyroidism to increase test numbers with same budget from 1995. 78 laboratories wanted to participate for neonatal screening test in 1999. Government decided to screen six items of PKU, congenital hypothyroidism, maple syrup urine disease, homocystinuria, galactosemia and congenital adrenal hyperplasia from 2006. In 2014, thirteen laboratories are participating. Inter laboratory quality control was started 6 times a year from 1994. In case a patient with an inherited metabolic disease is diagnosed by screening of government program, special milk is provided at government's expense. According to the government project, from 1997 to 2013, 7,080,569 newborns were screened. 144 PKU, 2.451 congenital hypothyroidism were detected. So incidence of PKU is 1/49,170 and congenital hypothyroidism is 1/2,888. The cost benefit of performing screening procedures coupled with treatment has been estimated to be as high as 1.77 times in PKU, 11.11 times in congenital hypothyroidism than cost without screening. By January 2007, many European countries had expanded of their newborn screening programs by inclusion of Tandem mass spectrometry. We are trying to increase the budget to test all newborns for Tandem mass spectrometry from 2016. We are considering four to five central laboratories which cover all newborns and are equipped with tandem mass spectrometer & enzyme immunoassay for TSH, 17OHP & enzyme colorimetric assay for galactose. And I hope to expand test including Wilson disease screening test and lysosomal storage diseases.