The evolution of young children's categories, as measured by category name production, was studied. The focus was on categories whose names initially were overextended. Four children (initially aged 1; 1 to 1; 3) were visited at home twice a week over a four- to six-month period, until they were approximately 1;7. The play sessions included eli-citations of the names of specially chosen objects. Results indicated that, as predicted, four sequences of category evolution were found, formed by the intersection of two factors: overlap vs. mutual exclusivity and first re-assignment separate vs. first re-assignment joint. As expected, most sequences involved initial overlap, and the choice of first reassignment option varied as a function of the relationship (hierarchical or non-hierarchical) between the initial child-basic category and the new category.