The purpose of this study was to examine whether phonological information was activated automatically in processing two-kanji compound words. In Experiment 1, 27 participants judged whether pairs of the words were homophones, while another 27 participants judged whether pairs were synonyms. Stimulus onset asynchrony (SOA) was 140 ms, 230 ms, or 320 ms. In Experiment 2, 36 participants were asked to make one of the two judgments, as in Experiment 1. SOA was determined individually. The following results were found. Reaction times showed semantic interference. Phonological interference was observed only under the shortest SOA in Experiment 2. Error rates showed phonological and semantic interferences even when SOA was the longest. These findings support the universal phonological principle.