A semiautomatic electronic blood cell counter (Sysmex F-800) was evaluated with equine blood, according to the protocol of the International Committee for Standardization in Haematology (ICSH, 1984). The precision and overall reproducibility were acceptable for all the parameters studied except for the platelet count, in which a coefficient of variation of 18.8% and 21.7% was obtained for within and between batch precision and 26.76% for overall reproducibility. Carry-over for the haematocrit value and platelet count was unsatisfactory, thus the use of a blank diluent sample between different analyses was necessary. Linearity of the analyser was acceptable in the range studied. A total of 100 equine blood samples were studied with the Sysmex F-800 and the manual method. The correlations between both Methods were acceptable for all the parameters. In the storage study, the red blood cell count and the haemoglobin concentration were the parameters with longest stability (72 h) at 4 degrees C and 25 degrees C. Platelet count decreased significantly at 3 h post-extraction in those samples stored at 4 degrees C. During the evaluation period, Sysmex F-800 was easy to handle and it is well suited for routine equine blood cell analysis.