The effects of annealing on photoluminescence (PL) spectra in CuInS2 crystals grown by the traveling, heater method have been investigated. After the CuInS2 crystals were annealed in a vacuum at 400 degreesC, a bound exciton emission at 1.525 eV (E-x2) was completely quenched and a new bound exciton peak (E-x3) appeared at 1.520 eV On the other hand, after annealing in contact with In2S3 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. (C) 2003 Elsevier Science B.V. All rights reserved.