Diminutives are very frequent in Croatian child language; children acquire them before they master many other elements of morphology. A great majority of diminutives used by the child are nouns. Although diminutives phonologically are more difficult than the simplex forms, diminutives make paradigms more transparent and reduce the number of noun classes. In this study the data of one Croatian girl were analyzed. The analysis includes frequencies, oppositions of diminutives and simplex forms, mini-paradigms and a comparison of child’s production and parental input.