The sulfurization behavior of SrTiO3 nanoparticles was studied by using a quartz spring-type thermobalance in CS2/N-2 atmosphere. The thermogravimetric curves showed the sulfurization of SrTiO3 nanoparticles occurred at a temperature range from 150 to 750 degreesC accompanied with the maximum weight increase of 20.7%. A mixed sulfide as Sr1.08TiS3 was formed during the sulfurization process, and it showed sulfur loss at higher temperatures forming Sr1.08TiS3-x as a final product at 1000 degreesC. In contrast, SrTiO3 powders with larger particles size showed sulfurization at temperatures ranging from 550 to 950 degreesC forming Sr1.08TiS3, and no sulfur loss was observed at higher temperatures. The difference found in the sulfurization behavior was assigned to not only the particle size but also the presence of OH groups in the SrTiO3 nanoparticles. During the sulfurization of calcined SrTiO3 nanoparticles, the removal of OH groups of SrTiO3 was found to produce an increment of the starting temperature of sulfurization. (C) 2004 Elsevier B.V. All rights reserved.