Use of microfabrication methods derived from the semiconductor industry have been adapted to new materials in the recent past to produce electromechanical and fluidic systems in the microscale. Polymers are one such class of new materials as they are considered more suited for biomedical applications due to low cost, abundance, and availability of a wide range of functionality in addition to properties such as low protein adsorption, chemical resistance, and low electrical and thermal conductivities. This chapter describes in detail the properties, microfabrication methods and applications associated with most of the widely used polymers such as polydimethylsiloxane, parylene, SU-8, hydrogels, biodegradable materials and thermoplastics.