A prototype of the CELL-DYN 3200 haematology analyser was evaluated in a tertiary care hospital laboratory. Precision, effects of sample ageing, linearity, carry-over, and comparability of cellular blood counts and five-part leucocyte differentiation were determined in accordance with the ICSH guidelines for the evaluation of blood cell analysers; the results were satisfactory for all parameters tested: haemoglobin concentration, RBC, MCV, WBC, platelet count, and counts of neutrophils, lymphocytes, monocytes, and eosinophils. Two-hundred and forty-seven routine blood samples were used for the comparability studies. The cellular blood count results from the CELL-DYN 3200 and the Bayer Diagnostic H-1 systems corresponded closely (correlation coefficient r > 0.96 for all parameters). For 201 samples without an instrument-generated suspect flag the same was true with regard to the differential parameters, although somewhat lower correlation was observed for monocyte counts (r = 0.88). Comparisons to 400-cell microscopic differentials gave similar results (r > 0.93 for neutrophil, lymphocyte and eosinophil counts). Our results suggest that the CELL-DYN 3200 analyser will serve the needs for automated blood cell counting and differential leucocyte counting in a tertiary care hospital laboratory.