Poly(L-lactide-co-ε-caprolactone) (PLCL, 75/25) solid and porous microspheres (MS) were prepared using solvent evaporation and gas foaming method, respectively. These MS were characterized for particle size, surface morphology, porosity, and surface area. Porous MS were modified by P-15 peptide using carbodiimide coupling method. These unmodified solid and P-15-modified/-unmodified porous MS were further evaluated for MG-63 proliferation, cell alignment, collagen type I expression, and matrix mineralization for 21 days. In vitro cell culture studies of P-15 functionalized porous MS exhibited enhanced cell viability, increased formation of actin filament bundles and collagen type I expression as compared to solid MS and 2D (polystyrene 24 well plate), and maintained the mineralization potential of MG-63 cells. The results suggests P-15-modified porous PLCL MS were able to grow the cells with proper cell functionality and hold potential to be used as an injectable cell carrier for bone tissue engineering applications. Copyright © 2010 John Wiley & Sons, Ltd.