Abstract: Objective To study the relationship between mothers’ A3243G mutation load and their offspring’s. Methods 50 families carrying A3243G mutation were recruited and A3243G mutation load were analysis. Result (1) A3243G mutation load in mothers’ blood correlated positively with that in offspring’s blood, the correlation coefficient r=0.438，P<0.01；(2) A3243G mutation load in mothers’ blood correlated positively with that in offspring’s urine, the correlation coefficient r=0.355，P<0.05；(3) In the families with 2 offspring, mutation ratio was higher in mothers having two affected children. Conclusion A3243G mutation load in mothers’ blood may have a positive correlation with the mutation load in blood and urine in their children.