Ten Trials of external quality assessment for clinical chemistry in general chemistry and blood gas were performed in 1999. All the control materials were sent in specifically-made boxes at the same time. The response rates were 72.4% in general chemistry and 87,5% in blood gas. The items included sodium, potassium, chloride, BUN, glucose, calcium, phosphorus, uric acid, creatinine, bilirubin, total protein, albumin, total cholesterol, triglyceride, AST, ALT, ALP, LD and GGT in general chemistry and pH, pCO2 and pO2 in blood gas. Compared with the previous year (1998), the methods of analysis are not changed much and the coefficient of variation and VIS scores of general chemistry items are increased.