In this paper, we present the EPFL combinational benchmark suite. We aim at completing existing benchmark suites by focusing only on natively combinational benchmarks. The EPFL combinational benchmark suite consists of 23 combinational circuits designed to challenge modern logic optimization tools. It is further divided into three parts. The first part includes 10 arithmetic benchmarks, e.g., square-root, hypotenuse, divisor, multiplier etc.. The second part consists of 10 random/control benchmarks, e.g., round-robin arbiter, lookahead XY router, alu control unit, memory controller etc.. The third part contains 3 very large circuits, featuring more than ten million gates each. All benchmarks have a moderate number of inputs/outputs ranging from few tens to about one thousand. The EPFL benchmark suite is available to the public and distributed in all Verilog, VHDL, BLIF and AIGER formats. In addition to providing the benchmarks, we keep track of the best optimization results, mapped into LUT-6, for size and depth metrics. Better logic implementations can be submitted online. After combinational equivalence checking tests, the best LUT-6 realizations will be included in the benchmark suite together with the author’s name and affiliation.