This chapter presents a general overview of pharmaceutically used polymers with respect to their physicochemical characteristics and factors affecting drug delivery abilities. Pharmaceutical polymers, chemical structure, and properties are discussed for their applications in controlled drug release systems. An additional focus is on new polymers (dendrimers, hyperbranched polymers), considering their chemical versatility, uniqueness, and future implications. Problems associated with controlled drug release systems are also highlighted. Finally, applications of FDA-approved polymers used for oral drug delivery systems are outlined.