Background eHealth presents opportunities to provide population groups with accessible health interventions, although knowledge about Internet access, peoples’ interest in using the Internet for health, and users’ characteristics are required prior to eHealth program development. Objective This study surveyed hospital patients to examine rates of Internet use, interest in using the Internet for health, and respondent characteristics related to Internet use and interest in using the Internet for health. For patients who smoke, preferences for types of smoking cessation programs for use at home and while in hospital were also examined. Methods An online cross-sectional survey was used to survey 819 orthopedic trauma patients (response rate: 72.61%, 819/1128) from two public hospitals in New South Wales, Australia. Logistic regressions were used to examine associations between variables. Results A total of 72.7% (574/790) of respondents had at least weekly Internet access and more than half (56.6%, 357/631) reported interest in using the Internet for health. Odds of at least weekly Internet usage were higher if the individual was born overseas (OR 2.21, 95% CI 1.27-3.82, P=.005), had a tertiary education (OR 3.75, 95% CI 2.41-5.84, P<.001), or was a nonsmoker (OR 3.75, 95% CI 2.41-5.84, P<.001). Interest in using the Internet for health increased with high school (OR 1.85, 95% CI 1.09-3.15, P=.02) or tertiary education (OR 2.48, 95% CI 1.66-3.70, P<.001), and if household incomes were more than AUS $100,000 (OR 2.5, 95% CI 1.25-4.97, P=.009). Older individuals were less interested in using the Internet for health (OR 0.98, 95% CI 0.97-0.99, P<.001). Conclusions Online interventions may be a potential tool for health care in this hospitalized population. Trial Registration Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12614001147673; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366829&isReview=true (Archived by WebCite at http://www.webcitation.org/6qg26u3En)