Optical sensors offer a wide field of application and are of potential utility in all kinds of analytical sciences. Typical area is pollution and process control, biotechnology, protection and defense, seawater analysis, clinical chemistry and invasive biomedical techniques. The interdisciplinary nature of optical chemical sensors opens a variety of new directions in sensor development. The issue of chemical selectivity is still the most challenging. There are several on-going directions for improving the selectivity of optical chemical sensors. One way is certainly in the field of supramolecular organic chemistry, and in the synthesis of the highly selective receptor molecules which will posses a chromogenic or fluorogenic part. Furthermore, biomonitoring can serve as a basis and the first step towards the development of “living sensors”. It is already a well-established in the field of environmental analysis and there are big potentials in the area of protection (DNA chips). In addition, the development in sensor materials opens a number of new possibilities, such as incorporation of organic and biochemical specific sites into inorganic matrices and all this knowledge could be resumed in development of new optical sensors based on molecular imprinted polymers. The recent progress in miniaturized integrated optical sensors offer several advantages, such as a possibility of mass-producing, low-cost sensor chips. By placing multiple sensing regions (sensing pads) on a single chip, the multi-component sensing with on-chip referencing becomes possible.