The aim of the study was to determine the effect of the thickness of litter on its physical parameters /temperature, heat loss, water and oxygen contents/ and thermic properties of the floors in standard laying houses at summer high temperatures. It was found that in shallow litter /up to 10 cm/ the inside temperaturo and external radiation temperature of the upper layer were significantly lower, heat loss being significantly higher, compared with those in deep litter /14-27 cm/. The thickness of the litter did not influence significantly its water and oxygen contents /15.30-31.49% and 17.82-20.80% respectively/. Morę favourable thermal conditions for laying hens were observed in shallow litters compared with those in deep litter.