We used data from the 2013 Montana Adult Tobacco Survey to estimate the prevalence of electronic cigarette (e-cigarette) use and reasons for initiation among Montana adults. More than 1 in 10 (11.2%, 95% confidence interval [CI], 9.1%-13.2%) adults reported ever using e-cigarettes, and 1.3% (95% CI, 0.7%-1.9%) reported current use. Most respondents reported "trying something new" (64%) or "trying to quit or reduce cigarette use" (56%) as a reason for initiating use. Ongoing surveillance of these addictive products is needed.