Context: The term software reuse was first used in 1968 at the NATO conference. Since then, work in the scientific literature have stated that the application of software reuse offers benefits such as increase in quality and productivity. Nonetheless, in spite of many publications reporting software reuse experiences, evidence that such benefits having reached industrial settings is scarce. Objective: To identify and classify the benefits transferred to real-world settings by the application of software reuse strategies. Method: We conducted a systematic mapping study (SMS). Our search strategies retrieved a set of 2,413 papers out of which 49 were selected as primary studies. We defined five facets to classify these studies: a) the type of benefit, b) the reuse process, c) the industry's domain, d) the type of reuse and e) the type of research reported. Results: Quality increase (28 papers) and Productivity increase (25 papers) were the two most mentioned benefits. Component-Based Development (CBD) was the most reported reuse strategy (41%), followed by Software Product Lines (SPL, 30%). The selected papers mentioned fourteen industrial domains, of which four stand out: aerospace and defense, telecommunications, electronics and IT services. The application of systematic reuse was reported in 78% of the papers. Regarding the research type, 50% use evaluation research as the investigation method. Finally, 13 papers (27%) reported validity threats for the research method applied. Conclusions: The literature analyzed presents a lack of empirical data, making it difficult to evaluate the effective transfer of benefits to the industry. This work did not find any relationship between the reported benefits and the reuse strategy applied by the industry or the industry domain. Although the most reported research method was industrial case studies (25 works), half of these works (12) did not report threats to validity.