The characteristics of anion exchange with internal HCO₃^-(or OH^-) was studied by determining the time course of hemolysis in isoosmotic ammonium salt solution in human erythrocytes. The effects of inhibitors, pH and temperature on the exchange between internal HCO₃^-(or OH^-) and external Cl^- were observed and the permeabilities of various organic and inorganic anions were also measured. The results were compared with data previously reported from the experiments using radioisotopes. The results are as follows; 1) SITS H₂DIDS and furosemide inhibited the hemolysis of erythrocytes in isoosmotic NH₄Cl solution in a dose¡¤dependent manner, and the concentrations for lengthening twice the time for half-hemloysis(t_½) were 2.3 X 10^-7, 1.3 X 10^-7 and 2.5 X 10^-5M , respectively. 2) Acetazolamide also shifted the time-dependent hemolytic curve to the right in a dose-dependent manner, and the concentrations for lengthening twice t_½ was 2.4 X 10^-5 M. 3) The time-dependent hemolysis was delayed by decreasing pH from 7.0 to 6.2, but w¡¤as not affected by the change of pH in the range of 7.0 to 8.2. 4) The time for half-hemloysis(t_½) showed a temperature-dependency and Arrhenius plot exhibited a break point at 20℃. The apparent activation energy calculated from this plot was 18.1 kcal/mol between 2℃-20℃ and 11.2 kcal/mol between 20℃-37℃, respectively. 5) The apparent permeabilities of various inorganic anions based on t_½ were in the order of Cl^->NO₃^->SCN^->SO₄^2->SSO₃^2->HPO₄^2-. which was similar with the previous reports based on the experiment using radioisotopes. The results Obtained from this study are comparable with the previous data reported from the experiments using radioisotopes. This indicates that the hemolysis of erythrocytes in isoosmotic ammonium salt solution can be used as a simple and good method for the study of anion exchange in erythrocyte membrane.