Methoxy poly(ethylene glycol)-b-poly(D,L-lactide-co-glycolide-co- ε-caprolactone) (MPEG-b-PDLLGCL) amphiphilic diblock copolymers were synthesized and used as nanosphere matrices. The drug-loaded nanospheres were prepared by the modified-spontaneous emulsification diffusion method without any emulsifiers for controlled drug delivery of poorly water-soluble model drug, indomethacin. Effect of DLL/G/CL ratio on nanoparticle and drug release characteristics was evaluated. The resultant drug-loaded nanospheres with average size in range of 126 - 134 nm had spherical in shape and smooth in surface. The drug entrapped inside the nanospheres had amorphous state. Drug loading efficiency was not found to be influenced by the DLL/G/CL ratio. The drug release profiles exhibited biphasic with a fast release followed by a slow release. The amounts of drug release increased when the G and CL units were incorporated in the polyester blocks. This indicates that MPEG-b-PDLLGCL nanospheres might be useful candidate as sustained drug carriers for poorly water-soluble drugs.