With the purpose of investigation on changes in growth pattern, bone marrow tissue culture was conducted at various intervals in leukemic patients who finally arrived at remission by antileukemic treatment. The growth pattern specific to leukemia was observed to change as the patients improved by the treatment. Further, the relationship between the changes in the growth pattern, and the various signs and symptoms and life span was studied. 1. The growth patterns at remission were classified into those four types according to the grade of the changes: leukemic, intermediate, normal and hypoplastic patterns. 2. It was demonstrated as the most effective way that acute leukemia was treated until the bone marrow growth pattern changed into the normal pattern and chronic leukemia until it turned into the hypolastic pattern.