It was desirable for each clinical laboratory to have its own normal ranges, though it may be cumbersome and cost-bearing. Patients' laboratory data of each test had recently been attempted by statistical analysis in an effort to obtain indirect estimates of the normal ranges. For this purposes the authors have tried to estimate normal values in our laboratory from routine clinical laboratory test items, using three statistical methods proposed by Hoffmann, Neumann and Chung. The laboratory studies were carried out by Abbott-VP biochemical analyzer at clinical laboratory, Busan National University Hospital from January, 1983 to August, 1983. The normal ranges estimated by the authors are as follows: 1) Normal ranges of serum total protein, album in and globulin are 5.8~5.0 and 2.0~3.6 gm/㎗, respectively. 2) Normal ranges of serum aspartate aminotansferase(AST) and alanine aminotransferase(ALT) are 9~30 and 9~34 IU/L. 3) Normal range of serum alkaline phosphotase(ALP) is 30~90 IU/L. 4) Normal range of serum lactate dehydrogenase(LD) is 95~200 IU/L. 5) Normal rage of serum gamma-glutamyl transpeptidase(GGT) is 10~43 IU/L.