The recent advance of polymer technology allowed the introduction of this type of optical fiber in sensors design. The advantages of optical metrology with plastic optical fiber have been calling the attention from the scientific community, as it allows the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. Several measurement techniques will be described with a strong focus on interrogation approaches based on intensity variation in transmission and reflection. A concise state-of-the art of potential applications will be presented, involving structural health monitoring, medicine, environment and biological and chemical area.