Macroporous poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) matrices were prepared after solvent evaporation and solute leaching. PHBV solutions with different concentrations were prepared in chloroform: dichloromethane (1:2, v/v). In order to create a matrix with high porosity and uniform pore sizes, sieved sucrose crystals (75-300 or 300-500 mum) were used. PHBV foams were treated with rf-oxygen plasma to modify their surface chemistry and hydrophilicity with the aim of increasing the reattachment of osteoblasts. Surface characteristics, pore sizes and their distribution on PHBV surface were studied by scanning electron microscopy (SEM) and Scion Image Analysis Program. Void volume, pore sizes and density of foams were found to be significantly affected by foam preparation conditions. Stability of PHBV foams in aqueous media was studied. Their weight and density were unchanged for a period of 120 days and then a significant decrease was observed for the rest of the study (60 days). Osteoblasts were seeded onto the foams and their proliferation inside the matrices was also determined by SEM. After 29 and 60 days of incubation, growth of osteoblasts on matrices was observed. (C) 2003 Elsevier Science Ltd. All rights reserved.