CMUT-on-CMOS integration is particularly suitable for catheter based ultrasound imaging applications, where electronics integration enables multiplexing capabilities to reduce the number of electrical connections leading to smaller catheter cable profiles. Here, a single-chip CMUT-on-CMOS system for intracardiac echocardiography (ICE) is presented. In this system, a 64 element 1-D CMUT array is fabricated over an application specific integrated circuit (ASIC) that features a programmable transmit beamformer with high voltage (HV) pulsers and receive circuits using 8:1 time division multiplexing (TDM). Integration of pitch matched 64 channel front-end circuits with CMUT arrays in a single-chip configuration allows for implementation of catheter probes with miniaturization, reduced number of cables, and better mechanical flexibility. The ASIC is implemented in 60 V 0.18 μm HV process. It occupies 2.6×11 mm ² which can fit in the catheter size of 9F, and reduces the number of wires from more than 64 to 22. This system is used for B-mode imaging of imaging phantoms and its potential application for 2D CMUT-on-CMOS arrays is discussed.