A new method of preparation of bulk amorphous solids is successfully applied to the semiconductor solid solutions Ge-1-X.(GaSb)(X). The method consists in the solid-state disordering of a high-pressure phase on decompression. Large mutual solubility can be achieved for high-pressure phases of Ge and GaSb. Amorphization of metallic solid solutions occurs on decompression even at room temperature. Some data concerning the structure and stability of the amorphous semiconducting solid solutions a-Ge-1-X(GaSb)(X) are presented.