Laccase-containing sol-gels were synthesized by hydrolysis and condensation-polymerization of tetramethylorthosilicates. Two types of laccase containing sol-gel based optical biosensors were designed and tested. The first type is based on 2–8 mm thick monolith sol-gel blocks. It was observed that laccase-containing sol-gel blocks accumulate high molecular weight products of oxidation of the laccase substrate - 2,6-dimethoxyphenol. This leads to at least ten fold increase of optical bioassay sensitivity in comparison with the homogeneous phase. The response time of such biosensors is 3–24 hours. The second type of biosensor is based on laccase-containing 0.3 mm diameter solgel particles in a flow cell and includes an optical fiber measuring system. This sensor is characterized by a fast response time in comparison with the first type. The latter biosensor also possesses a homogeneous phase assay sensitivity and yields a linear calibration curve.