This work reports on a heterogeneous integration of resistive memories into the Back-End-of-the-Line of 180nm standard CMOS foundry chips. A TaOx-based ReRAM technology with materials and processes fully CMOS compatible has been developed and characterized. A low-cost integration method is applied to the developed TaOx-based memories to achieve chip level ReRAM-CMOS integration. The integrated memory devices show working voltages compatible with CMOS circuits operations. Measured SET and RESET voltages of the ReRAM integrated cells are -1V and +1.3V, respectively, demonstrating suitability for low-voltage applications.