Based on Migen, MiSoC is a library of cores and a system-on-chip integration system to build gateware for various applications. MiSoC is lightweight (runs on FPGA devices as small as Spartan-6 LX9 with 32-bit RISC CPU and SDRAM), portable (demonstrated on Xilinx, Altera and Lattice devices) and high performance (e.g. contains the fastest open source DDR3 solution we are aware of). Designing and integrating cores is facilitated by Python and Migen features. Current MiSoC applications include LTE base stations, video processing (Numato Opsis) and experiment control system (ARTIQ).