Within　the　past　few　years,　chitosan-based　drug　delivery　vehicles　have　become　some　of　the　most　attractive　to　be　studied.　In　contrast　to　all　other　polysaccharides,　chitosan　has　demonstrated　its　unique　characteristics　for　drug　delivery　platforms,　including　its　active　primary　amino　groups　for　chemical　modification,　simple　and　mild　preparation　methods　for　the　encapsulation　of　biomolecules　or　drugs,　mucoadhesion　to　facilitate　transport　across　mucosal　barriers　and　so　on.　In　this　review,　an　overview　of　the　various　types　of　chitosan-based　drug　delivery　systems　is　provided,　with　special　focus　on　polymeric　drug　conjugates　and　drug　nanocarriers.　The　first　part　of　the　review　is　concerned　with　the　development　and　applications　of　polymeric　chitosan-drug　conjugates.　Then　the　chitosan-based　nanocarrier　systems　as　well　as　their　preparation　methods　and　applications　are　further　discussed.