Controlled drug delivery systems have received considerable attention in the last years as they provide a more controlled drug concentration at site of action leading to an improvement in the therapeutic outcomes. In this study, ciprofloxacin hydrochloride (Cip. HCl) microspheres were prepared using Eudragit RS 100 polymer applying the emulsion solvent evaporation method. The drug polymer ratios were selected to be 1:2 and 1:3.  Scanning electron microscopy (SEM), X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) analysis were used to characterize the obtained microspheres as well as the yield percent (%) and drug content. The in-vitro release patterns and the antibacterial activity of the formulated microspheres were also investigated. It was found that drug release was retarded by increasing the amount of the polymer and X ray diffractometry verified that there was no interaction between the drug and polymer. The antibacterial activity of the drug was improved as indicated by the increase in the inhibition zone diameter of the microsphere formulation.