Integrating electronic referral systems into clinical practices may increase use of web-accessible tobacco interventions. We report on our feasibility evaluation of using theory-driven implementation science techniques to translate an e-referral system (ReferASmoker.org) into the workflow of 137 community-based medical and dental practices, including system use, patient registration, implementation costs, and lessons learned. After 6 months, 2,376 smokers were e-referred (medical, 1,625; dental, 751). Eighty-six percent of the medical practices [75/87, mean referral = 18.7 (SD=17.9), range 0-105] and dental practices [43/50, mean referral = 15.0 (SD=10.5), range 0-38] had e-referred. Of those smokers e-referred, 25.3 registered [mean smoker registration rate-medical 4.9 (SD=7.6, range 0-59), dental 3.6 (SD= 3.0, range 0-