Recently, there are more and more research programs that treat Croatian as a foreign or a second language. The research programs are still in an initial stage, though, therefore there are not many test materials - or even clearly developed psycholinguistic methodology for systematic approach to this topic, especially when children are under investigation. A distinguished problem is a group of children that do not speak Croatian well enough to understand the school program and attend to Croatian schools. Lack of proper school program for Croatian as a second language and proper approach to teaching Croatian in this population contributes to the development of negative attitudes towards Croatian, avoidance of communication and, eventually, leaving Croatia in order to continue education in their own language. Hungarian minority nurture their language - of 16.596 Hungarians that live in Croatia, 12.650 speak Hungarian as a mother tongue. In this paper a field research results will be presented. The research was conducted on a population of Hungarian minority children that live in a village in Baranja, Croatia. Some non-standardized test materials were used to test their knowledge of Croatian and to predict their school success. Problems that were encountered will be discussed briefly.