An overview is given of intrinsic fiber-optic chemical sensing encompassing refractometric sensors, evanescent spectroscopic sensors, coated-fiber sensors, and core-based sensors. Specific attention is given to techniques that are being tested such as commercial fluoroimmunoassay probes, evanescent-wave sensors for monitoring composite curing, and liquid-level monitors based on refractometric sensors. Of particular interest in the realm of research are intrinsic fiber devices that employ dyes and similar intermediaries to enhance the response of the sensors. Sensors that employ such intermediaries are expected to provide greater sensitivity to target analytes. The sensor techniques presently under development are also concluded to be useful for air-quality monitoring, and specific projects are discussed that are aimed at sensing gaseous species.