The 2011 NSW election produced the largest two-party swing in recent Australian election history, ending 16 years of Labor government. It raises the prospect of the end of Labor's dominance of NSW politics. This paper focuses on the consequences of ALP instability for the Party's electoral opportunities and strategy in the lead-up to its 2011 defeat. The authors single out the mass departure of Labor MPs prior to the election and the loss of Greens preferences as interesting problems for empirical analysis. They explore both loss of incumbency and preference effects in a seat-level (n = 93) regression model and comment on the significance of the findings for NSW Labor.