Electronic cigarettes (e-cigarettes) are battery-powered devices that deliver nicotine in the form of aerosol. We identify differences and associations in e-cigarette use by sociodemographic characteristics and describe the reported reasons for initiating use among Mississippi adults. We used the 2015 Mississippi Behavioral Risk Factor Surveillance System, which collected information on e-cigarette use from 6,035 respondents. The prevalence of current e-cigarette use and having ever tried an e-cigarette was determined overall and by sociodemographic characteristics. Weighted prevalences and 95% confidence intervals were calculated, and prevalences for subgroups were compared using the X2 tests and associations were assessed using logistic regression. In 2015, 4.7% of Mississippi adults currently used e-cigarettes, while 20.5% had ever tried an e-cigarette. The prevalence of current e-cigarette use was significantly higher for young adults, whites, men, individuals unable to work, those with income $35,000-$49,999, and current smokers compared to their counterparts. Similar results were observed for having ever tried an e-cigarette. E-cigarette use was associated with age, race, income, and smoking status. Most (71.2%) of current e-cigarette users and over half (52.1%) of those who have ever tried e-cigarettes reported that a main reason for trying or using e-cigarettes was "to cut down or quit smoking."