The work in this thesis includes nullor synthesis, simulation and optimization of high order current-mode filter design procedures. Various techniques are established whereby these filters are synthesised with greatest precision and economy. A comprehensive mathematical formulation of an efficient nullor synthesis frame work is developed; under which these techniques are investigated. With the result of three design agendums that considers the various aspects and problems of designing high frequency state of the art active filters suitable for the increasing communication need. Each of the established techniques is carefully formulated, examined and used to realize active RCnullor networks capable of facilitating a given filter requirement. Realization of these RCnullor networks in current mode form furnishes the filter objectives. Processing current signals rather than voltage signals can result in networks operating with higher signal bandwidths, greater linearity and larger dynamic range. The current conveyor is an extremely powerful analogue building block with current-mode capabilities making it a potential candidate for implementing such nullor networks. Current conveyor based circuits will have performance superior to that of their op-amp of OTA counterparts. Many considerations have been discussed in the design of practical current-mode active filters; particularly for integrated circuit applications. A suitable predistortion technique has been considered to reduce the departure of the gain frequency response, from its ideal case, when commercial integrated current conveyors are used.