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Bacterial infection on implanted medical devices is a significant clinical problem caused by the adhesion of bacteria to the biomaterial surface followed by biofilm formation and recruitment of other cells lines such as blood platelets, leading to potential thrombosis and thromboembolisms. To minimize biofilm formation and potential devicebased infections, a polyurethane Biospan matrix was developed to release, in a controlled manner, an antibiotic ciprofloxacin™ locally at the implant interface. One material set consisted of the polyetherurethane PEU base matrix radiofrequency glow discharge plasma deposited with triethylene glycol dimethyl ether triglyme; the other set had an additional coating of polybutyl methyacrylate pBMA. Triglyme served as a nonfouling coating, whereas the pBMA served as a controlled porosity release membrane. The pBMAcoated PEU contained and released ciprofloxacin™ in a controlled manner. The efficacy of the modified PEU polymers against Pseudomonas aeruginosasuspensions was evaluated under flow conditions in a parallel plate flow cell. Bacterial adhesion and colonization, if any, to the test polymers were examined by direct microscopic image analysis and corroborated with destructive sampling, followed by direct cell counting. The rate of initial bacterial cell adhesion to triglymecoated PEU was 0.77, and to the pBMAcoated PEU releasing ciprofloxacin™ was 6 of the observed adhesion rates for the control PEU. However, the rate of adherent cell accumulation due to cell growth and replication was approximately the same for the triglymecoated PEU and the PEU controls, but was zero for the pBMAcoated PEU releasing ciprofloxacin™. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 50, 160–170, 2000.