Now that the measurement of Hb Aic has become routine in a diagnostic test for diabetes as part of a battery of tests in the physical checkup, we have come to know various factors cause Hb Aic values to fluctuate. Recently, we encountered a case in which the Hb Ale level is abnormally low. By isoelectric focusing, we identified Hb Malmo [β97 (FG4) His→G1n]. Some familial cases of Hb Malmo have been reported to be found in Sweden, Germany and Britain. It is first time that this case was discovered in Japan.