Biomedical micro-electromechanical systems or BioMEMS are microdevices with actuation or sensory function in biomedical applications. In this process, polymers are widely used as material layers. Polymers have significant advantages for applications in BioMEMS, such as low cost and ease of fabrication. The problem at the moment is the lack of information needed to compare polymers with each other in order to identify their characteristics and properties. These characteristics are particularly important for the biocompatibility of the BioMEMS. Therefore, the optical characteristics, surface characteristics, adhesion etching, and cytotoxicity are investigated. For the optical characteristics, the polymers were examined for fluorescence and transmission of light. For the surface characteristics, hermeticity (non-permeable) and wettability (hydrophilic or hydrophobic surfaces) were examined. Furthermore, adhesion and etching were studied for their (chemical) resistance. Finally, the polymers were examined for their toxicity to cells (cytotoxic). Through these tests, more information about the polymers and their characteristics has been obtained through these tests. The results of these different tests cannot be combined into a single polymer showing the best results from all tests. The fluorescence test showed that the layers of the final device are important as they can be responsible for different intensities of fluorescence. Furthermore, it was found that perminex is the most hydrophilic but may fracture in saline solution. It was noteworthy that the polymers, which are already widely used in BioMEMS applications (SU-8 and parylene-C), appeared to be the only ones to exhibit negative effects on cells (toxicity and cell growth inhibition). The other polymers tended to do significantly better there. Even though a number of properties that are important for biocompatibility were evaluated here, to ensure that the polymers and BioMEMS devices are fully compliant, testing will be required to meet the ISO standard 10993.