The objective of this article is to systematically review the currently available literature to formulate evidence-based guidelines for the treatment of femoral shaft nonunions for clinical practice and to establish recommendations for future research. Articles from PubMed/MEDLINE, Cochrane Clinical Trial Register, and EMBASE, that presented data concerning treatment of nonunions of femoral shaft fractures in adult humans, were included for data extraction and analysis. The search was restricted to articles from January 1970 to March 2011 written in the English, German, or Dutch languages. Articles containing data that were thought to have been presented previously were used once. Reports on nonunion after periprosthetic fractures, review articles, expert opinions, abstracts from scientific meetings, and case reports on 5 or fewer patients were excluded. The data that were extracted from the relevant articles included: type of nonunion, type of initial and secondary treatments, follow-up, union rate, and general complications. Most studies had different inclusion criteria and outcome measures, thus prohibiting a proper meta-analysis. Therefore, only the union rate and number of complications were compared between the different treatments. Methodological quality was assessed by assigning levels of evidence as previously defined by the Centre for Evidence-Based Medicine. This systematic review provides evidence in favour of plating if a nail is the first treatment; after failed plate fixation, nailing has a 96 % union rate. After failed nailing, augmentative plating results in a 96 % union rate compared to 73 % in the exchange nailing group.