In this sentence reading study, we used event-related potentials (ERPs) to investigate the processing mechanism of article-noun gender disagreement in two kinds of nouns in Italian. The first are nouns with syntactic gender (il treno(M) 'train' la sedia(F) 'chair') for which the processing and repair of gender disagreement entails only one repair option, namely for the article (morphosyntactic repair). The second kind are nouns with semantic gender (il bambino(M) 'boy', la bambina(F) 'girl'). Here, there are two options for processing and repairing gender mismatch: repairing the article (morphosyntactic repair) or repairing the noun (both morphosyntactic and semantic repair). Both classes of nouns elicited the LAN, indicating that gender disagreement is always registered at the morphosyntactic level. In addition, the P600 was elicited in both conditions, but was larger for semantic gender, reflecting a more complex repair for this class of nouns.