Quitlines are effective in helping smokers quit, but pediatrician quitline referral rates are low, and few parents who smoke use the service. This study compared enrollment of parents who smoke in the quitline using electronic referral with that using manual referral. The study was designed as a pragmatic RCT. Participants were recruited from one large, urban pediatric primary care site in Philadelphia, Pennsylvania with a high percentage of low-income families. Participants included adult parents who smoked and were present at their child's healthcare visit. Pediatricians screened for tobacco use; smokers were given brief advice to quit and, if interested in quitting, were referred to the quitline. The eReferral ("warm handoff") involved electronically sending parent information to the quitline (parent received a call within 24-48 hours). Control group procedures were identical to eReferral, except the quitline number was provided to the parent. Data were collected between March 2017 and February 2018 and analyzed in 2018. The primary outcome was the proportion of parents enrolled in quitline treatment. Secondary outcomes included parent factors (e.g., demographics, nicotine dependence, and quitting motivation) associated with successful enrollment. Number of quitline contacts was also explored. During the study period, in the eReferral group, 10.3% (24 of 233) of parents who smoked and were interested in quitting enrolled in the quitline, whereas only 2.0% (5 of 251) of them in the control group enrolled in the quitline-a difference of 8.3% (95% CI=4.0, 12.6). Parents aged ≥50 years enrolled in the quitline more frequently. Although more parents in the eReferral group connected to the quitline, among parents who had at least one quitline contact, there was no significant difference in the mean number of quitline contacts between eReferral and control groups (mean, 2.04 vs 2.40 calls; difference, 0.36 [95% CI=0.35, 1.06]). Smoking parent eReferral from pediatric primary care may increase quitline enrollment and could be adopted by practices interested in increasing rates of parent treatment.