Basketball is a popular sport in Australia. Although orofacial injuries are common, mouthguard (MG) wear in basketball appears to be low. The purposes of this study were: to measure mouthguard wear by basketball players before and after a promotional intervention; to assess players' knowledge of the value of mouthguards for prevention of injury; and to describe their experience of orofacial injury. Two questionnaires (baseline and follow-up) were administered to a convenience sample of 496 basketball players in Victoria, Australia. Players recruited were youths (12-15-year olds, n = 208) and adults (18 years and over, n = 288), from all basketball levels (social to elite). Completion of the baseline questionnaire was followed immediately by an intervention comprising written and verbal information, a mouthguard blank and instructions on mouthguard construction. The follow-up questionnaire was mailed to all respondents 10-12 weeks later; 135 youths (65%) and 157 adults (54%) completed this. Mouthguard wear at baseline was low but was more frequent at games (62%) than at training (25%). Despite 90% of players acknowledging the protective value of a mouthguard, wear by youths did not increase following the intervention, and wear by adults increased by only 14% for training and 10% at games. Previous orofacial injury was recorded at baseline by 23% of players, but few had requested compensation from Basketball Australia (youths, 17%; adults, 30%). Two predictor variables were statistically identified as related to mouthguard wear: previous orofacial injury and age group. Mouthguard wear was significantly more frequent amongst players with previous injury; such players were 2.76 times more likely to be wearers than those without previous injury. Youths were 2.31 times more likely to wear mouthguards than adults. Only 34 players (12% of respondents at follow-up) had a mouthguard constructed from the blank provided. Although youth and adult groups differed, the overall extent of mouthguard use was disappointingly low. Despite wide recognition of mouthguard value, the intervention had little effect on promoting their use.