The study aimed to examine the role of cases in the Croatian language (nominative, genitive and accusative) in the retention of information in long-term memory. This study examined whether the frequency of use of cases in the Croatian language affects the retrieval of information and how the delay in remembering affects memory performance. A sample of 74 undergraduate students of psychology participated in the research. The respondents were shown 60 sentences with target words in the nominative, genitive and accusative. Their task was to remember as many target words as possible. The subjects were tested for immediate recall and delayed recall one week after the presentation of the stimulus material. The results indicate that the target words in the nominative (the most frequently used case in the Croatian language) are memorized much better than genitives and accusatives. Followed by target words in the accusative, and then in the genitive. In addition, respondents came up with a larger number of words in all case forms during direct recall than during delayed recall. The findings suggest that the frequency of case use plays a key role in retaining information in long-term memory. In addition to the frequency of the case, the morphological form of the word is also important. Words in the nominative are monomorphological, while words in the genitive and accusative have inflexional morphology. Previous research, as well as this one, suggests a better memory of monomorphological words.