For detection of weak signals, and for use on ultralow temperature experiments, it would be useful to have a robust superconducting quantum interference device (SQUID) amplifier that works below 1 K. We report on a test of a commercial SQUID amplifier that has lower noise than others we have tested, and works well while attached to a 50‐mK chamber. The SQUID noise was improved only modestly when cooled from 4 K to 50 mK. The best energy resolution measured was 2200 ℏ.