To achieve greater coverage of elderly smokers and to shift entire populations toward cessation, the provider-client interface could be broadened beyond physicians to include nurses and social workers, who can be formally trained to provide such services. We carried out a population-based training needs assessment of the latter two groups in Hong Kong. Three thousand seven hundred eligible hospital-based nurses and 2,258 social workers who had elderly clients in Hong Kong were recruited in a knowledge, attitude, and practice (KAP) cross-sectional survey. We used multivariable logistic regression to identify predictors for two key outcomes-"initiation and advice" (ask and advise) and "follow-through" (assess, assist and arrange), based on the U.S. Agency for Health Care Policy Research framework. One thousand eight hundred forty-three (49.8%) nurses and 1,499 (66.4%) social workers responded. Nurses reported a much higher level of engagement in smoking cessation activities than social workers in all five steps of the AHCPR framework (P<0.001). Nurses (mean score=2.99+/-0.40 on a 4-point Likert scale) had more positive attitudes to tobacco control and smoking cessation counseling compared to social workers (mean score=2.79+/-0.41; P<0.001), whereas the latter group perceived themselves as more competent in handling such practice (mean score(nurses)=2.36+/-0.52, mean score(social workers)=2.51+/-0.39; P<0.001). Both attitudinal and self-perceived competence scores predicted incremental gains in the likelihood of offering "follow-through" interventions in addition to those observed for "initiation and advice" actions. Our findings highlight a large degree of unmet need in Hong Kong's hospital-based nurses and social workers who work with the elderly regarding smoking cessation service provision and training. Future research should focus on developing and evaluating programs that encourage nurses and social workers to provide cessation interventions to exert a much greater collective impact than doctors can alone.