UNLABELLED: Background Rates of gonorrhoea continue to rise among men who have sex with men (MSM) in Australia and worldwide. Recently, it has been proposed that oropharyngeal gonorrhoea may play a role in its onward transmission and that mouthwash use may be an effective intervention for gonorrhoea prevention and control. The objective of this study was to determine the association between specific oral sex practices and frequency of mouthwash use. METHODS: A questionnaire-based study was conducted among MSM attending the Melbourne Sexual Health Centre in Australia from March to September 2015. Logistic regression was performed to examine the association between frequent mouthwash use (i.e. daily or weekly mouthwash use) and four oral sex practices (tongue kissing, receptive fellatio with or without ejaculation, and insertive rimming) among MSM. RESULTS: Of the 918 MSM included in the final analysis, 490 men (53.4%) were frequent mouthwash users. Participants aged 24-34 years were 2.13-fold (95% CI 1.52-2.98) and those ≥35 years were 2.64-fold (95% CI 1.83-3.83) more likely to use mouthwash frequently than those aged ≤24 years. The most common oral sex practice was tongue kissing (n=874; 95.2%), followed by receptive fellatio without ejaculation (n=839; 91.4%), receptive fellatio with ejaculation (n=610; 66.5%), then insertive rimming (n=356; 38.8%). No significant association was found between frequent mouthwash use and tongue kissing, receptive fellatio with or without ejaculation, or insertive rimming with regular or casual male partners in the previous 3 months. CONCLUSIONS: Younger MSM are less likely to use mouthwash. There is no association between engaging in oral sex practices and frequent mouthwash use among MSM.