Telecom base stations are a critical part of society's information infrastructure. To ensure high quality base station software, automated testing is an important part of development. Ericsson measures the quality of automated tests with statement coverage, counting the number of statements executed by a test suite. Alone, however, statement coverage does not guarantee test quality. Mutation testing is a technique to improve test quality by injecting faults and verifying that test suites detect them. This thesis investigates whether mutation testing is a viable way to increase the reliability of test suites for base station software at Ericsson. Using the open-source mutation testing tool MiLu, we describe a practical method of using mutation testing that is viable for daily development. We also describe how mutation testing reveals a numbers of potential errors in the production code that current test suites miss even though they have very good statement coverage.