Purpose. Revealing the effect of the storage conditions for switchgrass seeds of different varieties and 1000-kernel weight on germination and seed vigour. Methods. Laboratory (determination of seed vigour and seed germination), measurement and weighting (determination of the 1000-kernel weight), and mathematical and statistical methods were used in the research. Results. It has been proven that seed vigour and germination naturally decreased along with a decrease in the 1000-kernel weight. On average, the lowest quality indicators were obtained for the seeds with the 1000-kernel weight of 1.24 g, however, during eight months of its storage, no natural decrease in the seed vigour and germination occurred. The quality of seeds with a greater 1000-kernel weight (1.67 g) was significantly higher and amounted to 55 and 58%. The smaller 1000-kernel weight, the lower was seed vigour and germination during storage for three and eight months was observed. No significant increase or decrease in seed quality was found depending on the 1000-kernel weight and the storage period. Similar results of the seed quality were obtained in the seed samples of different varieties. Seeds ‘Cave-in-rock’ variety with a 1000-kernel weight of 0.63 g had the lowest germination vigour, both at the beginning of the experiment and during eight months of storage; however, it did not depend on the storage period. Conclusions. On average of variety samples, a natural increase in seed vigour and germination occurs along with an increase in the 1000-kernel weight. At the same time, a natural increase in the seed quality of different 1000-kernel weight depending on the storage period was not found. On the contrary, seed vigour and germination were lower than in the control (at placing seeds for storage).