Background: While some smokers use e-cigarettes and stop smoking, a substantial proportion try e-cigarettes and later discontinue or use them concurrently with smoking (current dual users). The aim was to assess factors associated with ongoing e-cigarette use and discontinuation among smokers. Methods: Secondary analysis of data of 1489 currently smoking adults, 18 and above, from a GB population-based online survey conducted in March 2016. A multivariable logistic regression assessed motivation to stop smoking among never e-cigarette users, past triers (= weekly use), and current dual users. A multinomial logistic regression assessed associations of e-cigarette use status with motivation to stop smoking, reasons for use, age, gender, social grade, heaviness of smoking, and type of first e-cigarette used. Reasons for discontinuing use were assessed. Results: Current dual users were more motivated to stop smoking than past users (AOR = 1.95, 95% CI: 1.10-3.46); never users' or past triers' motivation did not differ from past users'. Dual users were less dependent on cigarettes (AOR = 0.54, 95% CI: 0.35-0.86) and more likely to use e-cigarettes as an aid to reduce smoking (AOR = 2.40, 95% CI: 1.59-3.64) and to deal with smoking restrictions (AOR, 2.03, 95% CI: 1.22-3.38) than past users. Smokers mostly discontinued e-cigarettes because they did not feel like smoking, did not help with cravings, or respondents had just wanted to try them. Conclusion: Among smokers, ongoing use of e-cigarettes is associated with reasons for reducing smoking and dealing with smoking restrictions, heightened motivation to stop smoking, and lower dependence on smoking. (C) 2017 The Author(s). Published by Elsevier Ireland Ltd.