The invention relates to a composition for producing transparent polythiourethane bodies containing or consisting of A) a polyisocyanate component containing at least one polyisocyanate with a functionality of isocyanate groups of at least 2 per molecule, B) a thiol component containing at least one polythiol with a functionality of thiol groups of at least two per molecule, in addition to optionally C) auxiliary agents and additives, the ratio of isocyanate groups to groups reactive in relation to isocyanates being 0.5:1 to 2.0:1. The composition is characterized in that the polyisocyanate of the polyisocyanate component A) is produced by a gas-phase phosgenation of aliphatic, cycloaliphatic, aromatic or araliphatic polyamines. The invention also relates to a method for producing transparent polythiourethane bodies by the conversion of a composition of this type, to polythiourethane bodies produced in this manner and to the use of polyisocyanates, produced by a gas-phase phosgenation of aliphatic, cycloaliphatic, aromatic or araliphatic polyamines, for producing transparent polythiourethane bodies.