The paper presents a theoretical background overview of the digital communication systems and the BPSK modulation and demodulation. The purposed design is the BPSK system. The BPSK modulation and demodulation represents an important modulation technique in terms of signal power. The BPSK system is simulated using Matlab/ Simulink environment and System Generator, a tool from Xilinx used for FPGA design as well as implemented on two Spartan 3E Starter Kit boards. The first board behaves as a modulator and the second as a demodulator. The modulator and demodulator algorithms have been implemented on FPGA using the VHDL language on Xilinx ISE 12.3. The local clock oscillator of the board is 50Mhz which corresponds with a period of 20ns. The frequency of the BPSK carrier is 31,250 kHz. Both, the modulator and demodulator, have been designed and simulated and theirs performances were evaluated by measurements.