Two trials of external quality assessment for the newborn screening tests of inborn errors of metabolism including PKU screening, TSH, T4 (total/free), galactosemia screen, maple syrup urine disease screen and homocytinuria screen and newborn screening tests using tandem mass spectrometry were performed in 2008. Total 20 specimens for the newborn screening tests were distributed to 14 laboratories. The response rate was 100%. All the control materials were sent as dried blood spot forms. The mean, SD, CV, median and range were analyzed. The newborn screening tests using tandem mass spectrometry (MS/MS) were analyzed that the participants results for amino acids, acylcarnitine and their cutoff values. In addition, two trial of external quality assessment for glycohemoglobin (HbA1c) was performed in 2008. Total five samples were distributed to 238 laboratories and the response rate was 95.8% (228/238) and 97.4% (225/231), in each. Statistical data such as mean, SD and CV were provided for peer groups.