This paper has two goals. First, it investigates Korean children``s knowledge of Binding Principles A and B. Secondly, it evaluates the validity of two competing hypotheses on acquisition of Principle A, the Subset Principle and the Relativized SUBJECT Theory, using four reflexives (caki, casin, caki-casin, and pronoun-casin). The two hypotheses have divergent predictions: the former predicts preference for local binding whereas the latter predicts a bias toward long-distance binding across the board. The results show that Korean children acquire Principle A prior to Principle B and that the children have clear preference for local binding throughout, supporting the Subset Principle.