The performance of the CELL-DYN 1700 (Abbott Diagnostics, Abbott Park, IL, USA) was evaluated in a tertiary care hospital laboratory using the guidelines proposed by the German Society of Clinical Chemistry. Precision, accuracy, linearity, background counts, and carry-over were satisfactory for all measured standard parameters including haemoglobin concentration, haematocrit, red blood cell count, mean corpuscular volume (MCV), red cell distribution width (RDW), white blood cell count and platelet count. With 259 selected normal and abnormal blood samples the results of the CELL-DYN 1700 (CD1700) compared very well (r > 0.96 for all parameters with exception of RDW) with those obtained with the Bayer Diagnostic H-1 and the Hoffmann-La Roche Cobas Argos systems. This study considered in particular the performance of the CD1700 three-part leucocyte differential. For those samples without instrument-generated suspect flags, the neutrophil and lymphocyte percentages were highly correlated with the results of the H-1 blood cell counter (r = 0.97 and 0.98, respectively) and with manual 400-cell differentials (r = 0.91 and 0.88, respectively). In contrast, the CD1700 mid-fraction which comprised the composite total of monocytes, eosinophils, basophils and precursor white cells (when present) could not be directly compared to the differentials from the H-1 system or from manual microscopy. For those samples with CD1700 instrument suspect flags, the neutrophil and lymphocyte differential results also compared well with both the H-1 (r = 0.93 and 0.93, respectively) and manual estimates (r = 0.89 and 0.87, respectively). In conclusion, the CD1700 is an accurate haematology analyser for cellular blood counts and three-part leucocyte differentiation.