The assessment of immunoglobulin content in colostrum is a routine procedure within Czech dairy farms, but little attention is paid to its microbial quality. The aim of the study Microbial contamination of colostrum from Czech dairy herds was quantitative and qualitative evaluation of bacterial contamination of colostrum from the first milking after calving. In 38 dairy herds of Holstein or Czech Fleckvieh breed 823 colostrum samples were examined from 2015 to 2017. The total plate count (TPC), coliform count (CC) and non-coliform count (NCC) in 1 mL was determined. In 108 samples the species of microorganism were determined and findings were classified into 4 groups – faecal contaminants, environmental contaminants, skin and mucosal microorganisms and mastitis agents. Only 27.7% of samples met the requirement of TPC below 100,000 cfu/mL, but 72.5 and 83.7% were below the limits of 10,000 and 5,000 cfu/mL for CC and NCC. The high proportions of samples (79.2%, 72.9% and 80,4%) contained faecal contaminants, environmental contaminants and skin and mucosal microorganisms.