Balling process in selective laser sintering of 316 stainless steel powder was investigated. It showed that the balling phenomenon was ascribed to the higher liquid viscosity and surface tension effect during laser sintering. The effects of laser power and scan speed on the balling initiation was studied. It was found that increasing laser power and scan speed within a moderate range can reduce balling effect. However, care should be taken to control laser powers and scan speeds that can be used since their excessive increase may give rise to detrimental effects.