The aim of the study was determine the effect of placing the floor gratings in calf hutches on selected microclimate indicators during the period of milk nutrition. Air temperature and relative humidity, temperature humidity index and Kata value were monitored in seven of calf hutches with and seven without floor gratings for two years. Obtained values were analysed by the StatSoft statistical package. The use of floor gratings in the calf hutches during mild winter led to a significant decrease of relative air humidity. Simultaneously there has not been proved the influence the use of floor gratings in calf hutches on the air temperature, the temperature humidity index and the Kata value in all monitored macroclimatic periods of the year (MRZ-freezing cold, MZ-mild winter, PO-transition period, ML-mild summer, HL-hot summer).