Nanocrystalline GaSb films were grown on Si(001) from the stoichiometric Ga⁻Sb mixture using solid-phase epitaxy at temperatures of 200⁻500 °C. Use of the solid-phase epitaxy method allowed the suppression of Ga surface diffusion and prevention of intense Sb desorption. At the annealing temperature of 300 °C, a 14-nm-thick GaSb film aggregates, while a 20-nm-thick GaSb film remains continuous with a roughness of 1.74 nm. A GaSb film with a thickness of 20 nm consists of crystalline grains with a size of 9⁻16 nm. They were compressed by ~2%. For some GaSb grains, new epitaxial relationships have been found: GaSb ( 111 ) ||Si ( 11 1 ¯ ) and GaSb [ 11 2 ¯ ] ||Si [ 1 1 ¯ 0 ] , GaSb ( 113 ) ||Si ( 11 1 ¯ ) and GaSb [ 1 1 ¯ 0 ] ||Si [ 1 1 ¯ 0 ] , and GaSb ( 11 1 ¯ ) ||Si ( 002 ) and GaSb [ 1 1 ¯ 0 ] ||Si [ 1 1 ¯ 0 ] .