Automated software test generation has been applied across the spectrum of test case design methods; this includes white-box (structural), black-box (functional), greybox (combination of structural and functional) and nonfunctional testing. In this paper, we undertake a systematic mapping study to present a broad review of primary studies on the application of search-based optimization techniques to non-functional testing. The motivation is to identify the evidence available on the topic and to identify gaps in the application of search-based optimization techniques to different types of non-functional testing. The study is based on a comprehensive set of 35 papers obtained after using a multi-stage selection criteria and are published in workshops, conferences and journals in the time span 1996–2007. We conclude that the search-based software testing community needs to do more and broader studies on nonfunctional search-based software testing (NFSBST) and the results from our systematic map can help direct such efforts.