The process of linguistic borrowing refers to the entry of words from one language, the donor language, into another, the recipient language. This ubiquitous phenomenon greatly affects speakers of a language, regardless of their age. National and international research shows that from the earliest age of language acquisition, i.e. preschool age, loanwords enter children's vocabulary. The aim of this study is to investigate the use of loanwords in preschool children depending on their age and gender as well as the socioeconomic status of their families. The study was conducted on language samples of spontaneous conversation from 61 children, 30 of whom were three-year-olds and 31 five-year-olds, and the loanwords used by the children in spontaneous speech were extracted from the samples. The results show that preschool children use loanwords in their spontaneous speech. In addition, five-year-olds were found to use loanwords significantly more often than three-year-olds. No difference in the frequency of use of loanwords was found between boys and girls. Due to the size of the sample from families of a lower socioeconomic status, it was not possible to draw conclusions about the use of loanwords depending on this factor. This study is a contribution to the understanding of vocabulary development in preschool children. The findings show that linguistic borrowing is common already at preschool age and that with increasing age, loanwords cover an even larger part of children's vocabulary.