A word can be pronounced by applying spelling-sound correspondence rules or by looking up its pronunciation in the lexicon. In contrast, a novel string with no lexical entry should be pronounceable only through rule application. Recent research, though, suggests that lexical information may contribute to the pronunciation of nonwords (Glushko, 1979; Marcel, 1980). The present three experiments tested this possibility with the logic of spreading activation. Experiment 1 found a decrease in naming latencies for target words preceded by either related words or pseudowords created from those words, implicating lexical activity in pseudoword pronunciation. In Experiment 2, words visually similar to target pseudowords were semantically primed prior to pseudoword presentation, but the expected facilitation in pseudoword naming did not appear. Experiment 3 provided strong support for the hypothesis, however, demonstrating a marked bias in the pronunciation chosen for an ambiguous pseudoword as the result of priming a visually similar word. © 1983 Psychonomic Society, Inc.