In the current experiment, participants read word-by-word sentences containing gender (adjective-noun) and number (article-noun) disagreement in Dutch while EEG was recorded. Number and gender disagreement were expected to elicit different responses due to several reasons. Firstly, gender is a lexical feature whose value (e.g., masculine or feminine) is stored in the lexicon, whereas number value is assigned depending on conceptual knowledge (numerosity). Also, Dutch marks number but not gender on the noun. Finally, due to the morphological nature of number, number disagreement provides more repair options than gender disagreement, thereby increasing the processing load. Both gender and number disagreement elicited a P600, but no LAN. The P600 effect was larger for number than gender disagreement in the late P600 stage. Since the observed effect was in the late P600 stage, we suggest that the most salient difference between the two types of disagreement lies in the increased repair complexity for number disagreement compared to gender disagreement.