With object of studying Zinc metabolism in leukemic patients the Zinc score in granulocytes was estimated by Mc Nary's method in Part 1. In the present experiment attempts were made to determine by atomic absorpiton spectrophotometry the serum Zinc content what is thought to be closely associated with Zinc metabolism, and the study was also made on changes in the Zinc levels according to types of diseases and to the results of treatment. Also Zinc contents in the urine and organs were estimated, though the cases studied were only a few in number. The relationship between Zinc score and serum protein picture was also investigated. Materials and Methods The subjects were all the patients admitted to the Second Department of Internal Medicine, Okayama University. They consisted of 9 cases of acute myelogenous leukemia (AML), 9 cases of acute lymphocytic leukemia (ALL), 4 cases of monocytic leukemia (MoL), 15 cases of chronic myelogenous leukemia (CML), 2 cases of chronic lymphocytic leukemia (CLL), and I case of erythrocytic leukemia (EL), to the total of 40 cases, as well as 6 cases of malignant lymphoma as related disease. For the control group 12 adult males and 15 adult females to the total of 27 healthy persons were selected. Results and Conclusion 1) It has been found that serum Zinc levels in healthy persons proves to be 134±12.2 mcg/dl in males and 113.8±16.4 mcg/dl in females, average being 119.2±16.5 mcg/dl. 2) The serum Zinc levels according to types of leukemia prove to be 106.9±31 mcg/dl in AML; 93.±32 mcg/dl in ALL, 81.7 mcg/dl in Mol, 111.1±31 mcg/dl in CML, 98.0±18 mcg/dl in GLL, and 62.5 mcg/dl in EL. 3) The serum Zinc score in leukemic patients is found to be low before treatment and at the time of aggravation in ALL and CLL, but it tends to recover to its normal level as the condition improves in both ALL and CLL. 4) There can be observed no significant correlations among the serum Zinc content, Zinc score of granulocytes, and alkaline phosphatase of neutrophils of the same leukemic individual. 5) There are also no significant correlations among the serum Zinc content, serum protein contents and their fractions in the same leukemic patient. 6) In studying (65)Zn-uptake by each protein fraction of leukemic patient serum after labeling it in vitro with (65)Zn, it has been demonstrated that the uptake by albumin is 52.7%, by α(1)-globulin 15.53%, by α(2)-globulin 18.62%, by β-globulin 9.19% and by γ-globulin to be 3.62%, indicating that the albumin fraction has taken up the major portion of (65)Zn, which is followed by the uptake of α(2)-globulin and α(1)-globulin. 7) In the study of absorption test and quantitative analysis of urinary Zinc contents after the administration of Zinc difference from the results with normal healthy control. 8) In estimating Zinc contents of erythrocytes, and leukocytes as well as Zinc contents in the liver, spleen, bone marrow and kidneys there can be observed no significant difference from the results with the normal control group. 9) It is assumed that disturbance of Zinc absorption and acceleration of its excretion, and the decrease in serum protein and albumin fractions are not mainly responsible for the mechanism of decreasing Zinc content in the serum of leukemic patient, but rather it is dependent upon other complex factors.