Nurses are expected to be involved in health promotion, including smoking cessation. This study aimed to assess nurses' knowledge, sense of responsibility and willingness to provide smoking cessation interventions as described in the national 5As guideline. Data were collected by a survey distributed to a convenience sample of nursing staff (n=162) from thirteen different adult acute care wards at a major metropolitan Melbourne hospital. Nearly all respondents (87%) agreed that they had a responsibility to counsel patients, and 22% were already doing so, but only 22% (n=36) of respondents demonstrated an adequate level of knowledge of smoking cessation. Nurses were more likely to counsel patients on health conditions related to their area of practice than those that were not. The findings indicate that greater emphasis is needed in undergraduate courses and in-service programs to increase nurses' awareness, and implementation of the 5As guideline for smoking cessation.