Standard haematological values have been calculated for female Holstein and Brown Swiss cattle kept at high altitudes in the Andean Sierra. Overall mean values were 5.9 x 10(12) l-1 for the red cell count, 0.321 l-1 for the packed cell volume, 9.6 gdl-1 for the haemoglobin concentration, 55.0 femtolitres for the mean corpuscular volume, 30.5 gdl-1 for the mean corpuscular haemoglobin concentration and 16.7 pg for mean corpuscular haemoglobin. Red cell indices tended to be higher in Holstein cattle than in Brown Swiss kept at the same altitude and were higher in cattle kept at higher altitudes. Mean white cell parameters were 9.7 x 10(9) l-1 for total white cells, 2.6 x 10(9) l-1 for neutrophils, 0.086 x 10(9) l-1 for bands, 6.3 x 10(9) l-1 for lymphocytes, 0.7 x 10(9) l-1 for eosinophils, 0.073 x 10(9) l-1 for monocytes and 0.001 x 10(9) l-1 for basophils.