OBJECTIVE: The aim of this study was to determine the appropriateness of messages on osteoporosis in Spanish videos posted on YouTube. METHODS: YouTube Spanish language videos on osteoporosis were evaluated. The main variable was the presence of appropriate messages related to osteoporosis. The content was evaluated through a checklist based on available guidelines and reviewed by an expert (E.C.L.). The evaluation was performed twice independently for each video. A discussion of discordant messages was made with the expert. Other variables included were number of views, comments, "likes," and "dislikes"; the total duration of the video; and their source (health professionals and non-health professionals). Bivariate analysis between health professionals and non-health professionals were performed using the Mann-Whitney U and the χ tests. RESULTS: A total of 148 videos were reviewed. The median appropriate score for all videos was 5 (p25: 3, p75: 9) (maximum possible, 29 points). Seventy-three (49%) videos had a health professional as source, 124 (83.8%) mentioned at least one message in the definition area, 99 (66.9%) in the area of diagnosis, 99 (66.9%) in the area of recommendations, 43 (29.1%) in the area of treatment, and 5 (3.4%) in follow-up. The most frequent message was "risk of fracture" (68.9%). CONCLUSIONS: The content of osteoporosis information found in YouTube was generally incomplete and inaccurate. The content of these videos should include treatment and preventive strategies.