Reference intervals are presented for 14 hematology and 32 biochemistry variables from four age groups of female Holstein cattle (n = 172) selected randomly from six well managed farms. Each animal was examined by a clinician and with the history available considered to be clinically normal at the time of blood collection. The variable observations were examined for outliers and Gaussian distribution prior to parametric or where necessary, nonparametric analysis. Many differences were noted between age groups but few between farms.