In the first experiment, we analyzed 418 samples of maize silage, half in the range 28 to 34% DM (dry matter), the other half from 34 to 40%. Higher DM (34 – 40%) was significantly negative influence on the chemical composition and fermentation quality of maize silage. Increasing DM had very little impact on changing the content of NDF (neutral detergent fiber), starch and OM (organic matter). While DM increased, content of NDF, starch and OM were around the same level. In the group of samples with 34 – 40% DM was observed trend of increasing pH. In the second experiment, we analyzed 60 samples of maize silage from 25 to 45% DM. The trend showed that increasing DM has very little effect on the digestibility (in sacco) of OM, but a high effect on the digestibility of fiber, it decreased while DM increased.