This garduate thesis deals with an analysis of the morphosyntax of learners of Croatian as a second language. The aim of the paper is an estimation of the Croatian morphosyntax of primary school students with the Janjevo language as their first language who learn Croatian at school, as well as a comparison of their morphosyntax with the one of students with Croatian as their first language. 7 students of Janjevo origin and 7 students with Croatian as their first language, who were second grade students at the time, took part in the study. For the purpose of the study the students' short essays were collected which had been written during Croatian lessons at school. The essays were then analysed on the morphosyntax of the written language. The results of the text analysis show that both groups made mistakes in the area of Croatian morphology, however, only the Croatian as a second language group made mistakes in marking the gender, number, case and person, which can be ascribed to the tendencies of Janjevo language speakers to simplify the declination of the Croatian language. As for the complexity of the syntax of the studied texts, there were double as many complex sentences produced by the experimental group, which in this case is not a proof of a more successful acquisition of the syntactic structure by the experimental group, but of a weaker skill of establishing a relationship between sentence parts. Taken together, the results suggest that there are certain parts of the Croatian grammar which are problematic to students of Janjevo origin and by which they differ from students with Croatian as their first language.