This chapter describes the design of PRNGs using chaotic maps and chaotic systems. The first PRNG uses a 2D map and the second and third PRNGs use maps without fixed points and are simulated in fixed-point arithmetic. Analyzing the first PRNG, one can appreciate the advantage of using fixed-point arithmetic instead of floating-point numbers. The FPGA synthesis of the first PRNG is detailed along the Verilog description. The chapter follows describing NIST and TestU01 tests for the 3D Lorenz system, which is also synthesized into an FPGA along its Verilog description. The FPGA synthesis of PRNGs based on 4D and 5D chaotic systems is also described, and their experimental results are provided.