Poly (dimer acid-sebacic acid) P(DA-SA) copolymers have been prepared by melt polycondensation of the corresponding mixed anhydride prepolymers. The copolymers were characterized by FT-IF, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). In vitro studies showed that all the copolymers are degradable in phosphate buffer at 37 C, and leaving an oily dimer acid residue after hydrolysis for the copolymer with high content of dimer acid. The release profiles of hydrophilic model drug, ciprofloxcin hydrochloride, from the copolymers, follows first order release kinetics. The in vivo biocompatibility of the copolymer in rabbit brain was also evaluated, macroscopic observation and microscopic analysis demonstrated that the copolymer is biocompatible and well tolerated in vivo. All the preliminary results suggested that the copolymer might be potentially used as drug delivery devices for brain implantation.