The tissue culture technique is widely used in biochemical and molecular studies, offering accessibility to biological material, high reproducibility of results and high throughput format, comparing with organ cultures. However, traditional, two-dimensional cultures (2D cultures) poorly represent the microenvironment of a tissue, and they are gradually replaced with 3D cultures, that enable formation of intercellular contacts, signaling pathways and gene expression characteristic for tissue in vivo. This paper presents the biology of three-dimensional cultures (spheroids), their applications in basic science and biotechnology and methods of spheroids formation.