Regular and highly interconnected macroporous scaffolds ranging in size from 50 to 150 mum were fabricated from poly(D,L-lactic acid-co-glycolic acid) (PLGA)-dioxane-water ternary systems via thermally induced phase separation (TIPS) without any surfactant or other additives. The effect on scaffold morphology of processing parameters including quenching temperature, polymer concentration, solvent composition and molecular weight, was investigated as a function of quenching time. The cloud-point temperature of the polymer solution was found to depend on polymer concentration, solvent composition, and polymer molecular weight. The water content in the solvent mixture had the greatest effect on the cloud-point temperature. The optimal quenching temperature for preparing macroporous interconnected scaffolds from a 9 wt% PLGA solution (dioxane-water = 87/13, by wt) was less than - 7 degreesC. In low viscosity PLGA solutions, sedimentation of the polymer rich phase occurred due to the segregation of the separated phases under gravity. This led to the formation of scaffolds with irregular and closed pores. (C) 2003 Elsevier Science Ltd. All rights reserved.