A new architecture is proposed for achieving Simultaneous Transmit and Receive (STAR) with a digital phased array. We demonstrate how digital beamforming and cancellation enables adjacent transmitting and receiving sub-arrays to operate simultaneously in the same frequency band without a significant reduction in performance. Our approach uses only digital signal processing techniques and does not require custom radiators or analog cancelling circuits that can increase front-end losses and add significant size, weight and cost to the array. Simulated results are presented for a 50-element array that achieves more than 160 dB of effective isolation between transmit and receive beams over a 100 MHz instantaneous band centered at 2.45 GHz.