The aim of the study was to evaluate the effect of ensiling density on chemical and microbiological characteristics of sorghum silage. Thirty-six minisilos made of PVC with a volume of 3.1 dm³ were used. A completely randomized design was used with six replications per each treatment. The treatments differed in packing density: 300, 375, 450, 525, 600 and 675 kg of fresh forage per m³. The contents of dry matter (DM), crude protein and the count of lactic acid bacteria tended to increase with increasing packing density. The highest DM contents were observed for silages with density of 525 kg · m⁻³. The contents of organic matter, water-soluble carbohydrates, ammoniacal nitrogen, acid detergent fibre, hemicellulose, cellulose and nitrogen insoluble in neutral and acid detergents were not affected by silage density. However, the contents of neutral detergent fibre, lignin, pH values, yeast and mould counts and the DM losses tended to decrease together with increasing silage density. It was observed that the silage with the highest density resulted in lower DM losses when compared to the silage densities lower than 525 kg · m⁻³. So, it can be stated that the minimum density of sorghum silage ensuring its quality is 525 kg · m⁻³.