Research objective: The objectives of this research were to determine the proportion of lymphocyte-type effusions (LPI) in total pleural effusions (PI), the proportion of cytologically diagnosed malignancies in total LPI and to determine the distribution of LPI by age, sex and clinical diagnosis. Materials and methods: The study included 116 PI samples analyzed at the Department of Clinical Cytology, University Hospital Center Split from January 1 to December 31, 2021. Of that number, there were 69 samples with a diagnosis of LPI that were further statistically processed. Clinical data were obtained from the archives of medical records. PI sampling was performed at the Department of Pulmonology, University Hospital Center Split, and samples were analyzed according to standard cytomorphological criteria at the Department of Clinical Cytology, University Hospital Center Split. Results: Of the 116 PI samples, 69 were LPI (59.5%). The average age of the patients was 72 years (SD = 11,247). The distribution of LPI by gender was approximately equal, men (53.6%) and women (46.4%). 7 (10.2%) patients had previously been diagnosed with Covid-19. Of these, 4 patients (5.8%) had a history of malignant diagnosis in addition to Covid-19, and 3 patients (34.35%) had no malignant diagnosis. Of the other diagnoses in the history of the disease, the most common were cardiovascular diseases (20.6%), benign neoplasms (17.5%) and respiratory diseases (12.2%). Conclusion: Cytology plays a significant role in diagnosing the causes of pleural effusions. Cytological analysis can make a definitive diagnosis in a quick, simple, and highly specific way. In malignant effusions, it can determine the origin of malignant cells and thus determine the basis of the disease. Cardiovascular disease has been found to be the most common non-malignant cause of both PI and LPI. Covid-19 is a new disease and therefore there is not much research on the association of Covid-19, pleural effusions and malignancies. In this study, 10.2% of the patients examined had Covid-19. 5.8% of patients also had a history of malignancy. Further research is needed to determine the possible association of Covida-19 and pleural effusions.