Rationale: Smoking cessation interventions in outpatient settings have been demonstrated to be cost effective. Given this evidence, we aimed to evaluate the effectiveness of varenicline tartrate plus Quitline-counselling compared with Quitline-counselling alone when initiated in the inpatient setting. Methods: Adult patients (18-75 years) admitted with a smoking-related illness to three hospitals, were randomised to receive either 12-weeks of varenicline tartrate plus Quitline-counselling, (n=196) or Quitline-counselling alone, (n=196), with 12-months follow-up. Results: For the primary analysis population (intention-to-treat), the proportion of subjects who remained continuously abstinent were significantly greater in the varenicline plus counselling arm (31.1%, n=61) compared with counselling alone (21.4%, n=42; RR 1.45, 95% CI 1.03 to 2.03, p=0.03). Conclusions: The combined use of varenicline plus counselling when initiated in the inpatient setting has produced a sustained smoking cessation benefit at 12-months follow-up, indicating a successful opportunistic treatment for smokers admitted with smoking related illnesses.