Children with primary language impairment (LI) show a deficit in processing various grammatical structures, verb inflections, and syntactically complex sentences among other things (Clahsen-Hansen 1997; Leonard et al. 1997). Cross-linguistic research has shown that the pattern of performance is language-specific. We examined grammatical sensitivity to word order and agreement violations in 50 Hungarian-speaking children with and without LI. The findings suggest a strong association between sensitivity to grammatical violations and working memory capacity. Variations in working memory performance predicted grammatical sensitivity. Hungarian participants with LI exhibited a weakness in detecting both agreement and word order violations.