The effects of annealing on photoluminescence (PL) spectra in CuInS 2 crystals grown by the traveling heater method have been investigated. After the CuInS 2 crystals were annealed in a vacuum at 400 o C, a bound exciton emission at 1.525 eV (E x 2 ) was completely quenched and a new bound exciton peak (E x 3 ) appeared at 1.520 eV. On the other hand, after annealing in contact with In 2 S 3 powder, PL spectra of exciton emission did not exhibit significant changes. From the results, the origins of the defects associated with bound excitons have also been discussed.