A new instrument was devised to investigate receptive phoneme-sequencing knowledge of a group of normally articulating children of kindergarten and elementary school age. Phoneme sequences, in the initial or final position of monosyllabic nonsense syllables that either adhered to or violated the phoneme-sequencing rules of American English, were tested. Older children correctly identified significantly more phoneme sequences than younger children. All children correctly identified significantly more impossible phoneme sequences than possible sequence items. Children did not abstract and internalize the rules for sequencing phonemes on a level comparable with that for adults until the ninth or tenth year of life. Decision-making strategies used by children to identify phoneme sequences were discussed.