Quality control of subtitles is a relatively unresearched field, even though it has a significant influence on the overall quality, and thus viewers’ experience of subtitles. It is carried out in different ways: various language service providers and broadcasters have different procedures, for instance, it sometimes solely involves proofreading. An online questionnaire has been distributed among professionals involved in the production chain of subtitles: broadcasters, streaming and video-on-demand services, vendors also known as language service providers, subtitlers, quality controllers, and proofreaders. The hope is that this report will enable professionals involved in quality control of subtitles to further enhance their quality control procedures. The results of this research could also be used in experimental investigation of viewers’ perception of quality in subtitling by using the same research methods applied in this study.