A room-temperature high-pressure synthesis method is proposed as an alternative way to induce nanoscale structural disorder in the bulk thermoelectric CuInTe2 matrix. This disorder stems from the coexistence of distinct domains with different degrees and geometries of disorder at Cu/In cation sites. The lattice thermal conductivity of high-pressure-treated CuInTe2 is substantially less than that of hot-pressed CuInTe2. The Debye-Callaway model reveals that the reduced lattice thermal conductivity is mainly attributed to disorder at the Cu/In cation sites and stacking faults, which were probably created during formation of the high-pressure-treated phases. This study demonstrates that room-temperature high-pressure synthesis can produce a radical change in the crystal structure and physical properties of conventional thermoelectric materials.