The present study used a mediated priming paradigm to examine whether developmental differences exist in the integration of semantic information with orthographic and phonological information during visual word recognition. In Experiment 1, we found that the integration of semantics with phonology and orthography differed among third-grade, sixth-grade and college students: orthographically based mediated inhibition effects were found in third-grade children, whereas phonologically based mediated inhibition effects were found in sixth-grade children and college students. A second experiment was performed with adults to test the hypothesis that the orthographically based mediated inhibition effect observed with young children was due to deficits in orthographic processing. When stimulus quality was manipulated within the mediated priming paradigm, orthographically based mediated inhibition effects were found when targets were dim, whereas phonologically based mediated inhibition effects were found when targets were bright. Taken together, these results suggest that the allocation of activation during reading may depend on the processing demands of the word recognition system.