Three experiments are reported that extend previous observations on the slowing of lexical decisions by phonologically ambiguous forms of Serbo-Croatian words relative to the phonologically unambiguous forms of the same words. The phonological ambiguity arises from the presence of letters whose phoneme interpretation differs between the two Serbo-Croatian alphabets, the Roman and the Cyrillic. In the first experiment, target words were preceded by asterisks or by context words that were associatively related and alphabetically matched to the targets. The effect of word contexts (i.e., priming) was greater for phonologically ambiguous than for phonologically unambiguous targets. The second experiment manipulated the alphabetic match of context word and target word. The effect of this manipulation was limited to phonologically ambiguous words. The third experiment reproduced the details of the first with the addition of visual degradation of the target stimuli on half of the trials. The results of the first experiment were replicated but no interaction between context and visual degradation was observed. The discussion focused on phonologically mediated access of Serbo-Croatian words. A model was proposed in which phonological codes are assembled prelexically according to weighted grapheme-phoneme correspondence rules.