【abstract】Objective To evaluate side effects and complications of hysterosalpingocontrastsonography (HyCoSy). Methods 356 infertile women were examined by HyCoSy and monitored for at least 30 minutes after the procedure. Tolerability to the procedure was evaluated by means of an 11-point numeric rating scale (NRS) of the pain experienced. The statistic differences between side effect and tubal patency were analyzed. Results Of 356 patients, 151 (42.4%) complained obvious pain and 32 (9.0%) experienced mild vasovagal reactions. There was a significant difference on pain experience and vasovagal reactions between patients with patent tubes and those with obstruct tubes. The main late complications were vaginal bleeding for more the 3 days in 13 patients and 1 with acute pelvic phlogosis. Conclusion In our series, HyCoSy was a safe examination; its side effects were pain and vasovagal reactions, which was mainly caused by obstructed tubes. Late complications were very few.