This study was carried out to determine the effects of silage material type, packing pressure and storage duration on crude nutrients contents and qualities of silages. Therefore, 2 different sized copped green corn (A: 13 mm and B: 17 mm) and 2-month-fermented corn (C) in a conventional silo were packed under the pressures of 130, 150 and 160 bar into 40 kg capacity polythene bags and then stored for 2, 4 and 12 months in a packing plant. Crude protein (CP), crude cellulose (CC), crude ash (CA), crude fat (CF), metabolic energy (ME), dry matter (DM), acetic acid (AA), butyric acid (BA) and lactic acid (LA) levels, pH values and Flieg scores of silages were determined at the end of every storage duration. There were significant differences in CP (P<0.05), CC (P<0.01), CA (P<0.01), CF (P<0.01), ME (P<0.01) and DM (P<0.01) levels of silages at different silage material types. Storage duration affected CP (P<0.01), CA (P<0.01), CF (P<0.01) and DM (P<0.01) levels of silages, whereas no significant differences were detected in CC and ME levels of silages between storage durations. Packing pressure did not affect CP, CC, CA, CF, ME and DM levels. AA (P<0.01) and LA (P<0.05) levels and pH values (P<0.01) changed depending on silage material type, whereas silage material type did not affect BA levels. Packing pressure did not also affect AA, LA and BA levels and pH values. Storage duration affected AA (P<0.01) and BA (P<0.05) levels and pH values (P<0.01), whereas no significant differences were found in LA levels between storage durations. Flieg scores were affected by silage material type (P<0.05) and storage duration (P<0.01). This study demonstrated that the best quality silage with high nutrient content can be obtained from green corn that were packed under 150 bar pressure immediately after copped and stored for 4 months.