Background: We evaluated the body fluid (BF) module on the new Sysmex XN-1000 for counting blood cells. Methods: One hundred and eighty-seven BF samples [73 cerebrospinal fluid (CSF), 48 continuous ambulatory peritoneal dialysis (CAPD), 46 ascites, and 20 pleural fluid] were used for method comparison between the XN-1000 and manual microscopy (Fuchs-Rosenthal chamber and stained cytospin slides) for counting red blood cells (RBCs) and white blood cells (WBCs) (differential). Results: Good agreement was found for counting WBCs (y=1.06x + 0.09, n=67, R 2 =0.96) and mononuclear cells (MNs) (y=1.04x–0.01, n=40, R 2 =0.93) in CSF. However, the XN-1000 systematically counted more polymorphonuclear cells (PMNs) (y=1.48x + 0.18, n=40, R 2 =0.99) compared to manual microscopy. Excellent correlation for RBCs >1×10 9 /L (y=0.99x + 116.56, n=26, R 2 =0.99) in CSF was found. For other fluids (CAPD, ascites and pleural fluid) excellent agreement was found for counting WBCs (y=1.06x + 0.26, n=109, R 2 =0.98), MNs (y=1.06x–0.41, n=93, R 2 =0.96), PMNs (y=1.06x + 0.81, n=93, R 2 =0.98) and RBCs (y=1.04x + 110.04, n=43, R 2 =0.98). By using BF XN-check, the lower limit of quantitation (LLoQ) for WBC was defined at 5×10 6 /L. Linearity was excellent for both the WBCs (R 2 =0.99) and RBCs (R 2 =0.99) and carry-over never exceeded 0.05%. Conclusions: The BF module on the XN-1000 is a suitable tool for fast and accurate quantification of WBC (differential) and RBC counts in CSF and other BFs in a diagnostic setting.