Outbreaks of the Pacific Crown-of-thorns Starfish Acanthaster cf. solaris are a major contributor to the sustained loss of coral, and the long-term degradation of Australia's Great Barrier Reef. There is a major imperative to reverse continuing coral loss on the reef, thereby justifying ongoing and increasing efforts to cull these starfish, which otherwise predate on reef-building corals. Long-term prevention of outbreaks will require unequivocal resolution and effective actions to manage the factor(s) that initiate or exacerbate outbreaks of Crown-of-thorns Starfish. Meanwhile, direct culling (mostly by administering a lethal injection) remains the most effective mechanism to control outbreaks. The efficiency and effectiveness of the established culling program on the Great Barrier Reef was given an enormous boost in recent years, owing to the development of the “single-shot” injection method. There has since been an increased investment in culling effort. Nonetheless, the rationale and effectiveness of the ongoing and expanding culling program is equivocal and further consideration must be given to when and where to allocate culling effort to maximise ecological and economic benefits.