The MC14518B dual BCD counter and the MC14520B dual binary counter are constructed with MOS Pchannel and Nchannel enhancement mode devices in a single monolithic structure. Each consists of two identical, independent, internally synchronous 4stage counters. The counter stages are type D flipflops, with interchangeable Clock and Enable lines for incrementing on either the positivegoing or negativegoing transition as required when cascading multiple stages. Each counter can be cleared by applying a high level on the Reset line. In addition, the MC14518B will count out of all undefined states within two clock periods. These complementary MOS up counters find primary use in multistage synchronous or ripple counting applications requiring low power dissipation and/or high noise immunity.