This study focuses on the assessment of working memory and linguistic skills in 21 Italian-Russian speaking bilingual children who were born in Italy and inherited Russian from their parents. Their performance was compared to that of 21 monolingual Russian-speaking and 21 monolingual Italian-speaking peers. For the assessment of the two languages (Russian and Italian) in bilinguals and the respective languages (Russian OR Italian) in monolinguals, the equivalent forms of the same battery of tests were used. Overall, the bilinguals showed enhanced verbal working memory with respect to Italian monolinguals but not Russian ones. The lexical skills of the participants in the bilingual group, as measured via semantic fluency, naming and lexical comprehension, appeared to be rather limited in Russian when compared to those of the monolingual group. Their vocabulary was mainly made of words with medium-to-high frequency. Passive, reversible and negative sentences appeared to be the most difficult for the participants who inherited Russian from their parents. The findings are discussed in the light of current theories of heritage languages acquisition.