Twelve-hour shift rostering offers an alternative to the traditional 8- and 10-hour shifts usually worked in Australian nursing practice. This paper outlines the implementation process involved in introducing 12-hour shifts in a Melbourne hospital intensive care unit. The process was instigated by the nursing staff. After extensive consultation with the union and hospital management, a roster pattern of two 12-hour days, followed by 12-hour night shifts then days off, was introduced. Independent researchers were engaged to evaluate the impact of the 12-hour shifts on staff well-being and work performance. Effects on staff retention, sick leave and inservice education were examined. The researchers found that well-being and work performance were minimally affected by the 12-hour shift roster, while staff retention and sick leave were unaffected. Further, the pattern of 12-hour shifts, which was democratically implemented, was preferred by the nursing staff and did not diminish their well-being and work performance.