Cell counts in body fluids provide information to clinicians for diagnosis and treatment of a wide variety of medical conditions. Routinely, the analysis of cell counts is performed manually using a haemocytometer due to numerous limitations in manual inspection and counting. Automated counters are therefore employed to perform the test faster and with more accuracy. OBJECTIVE To compare the results of manual and automated White Blood Cell (WBC) counts in serous body fluids. METHODS A prospective study of 130 samples were performed manually using the improved Neubauer chamber with the same samples also being analysed on Sysmex XT-4000i. RESULTS It was observed that there is a statistically significant correlation between the values obtained in peritoneal and pleural fluids, but this is not the case with cerebrospinal fluid. CONCLUSIONS The Body Fluid Mode (BFM) of the Sysmex XT-4000i is a fast, reliable and accurate to count WBC's in body fluids.