SummaryAn account of the 15 muttonbird colonies on Phillip Island, Victoria, is presented. The history of these is briefly discussed in relation to the island's history, and compared with the present situation. While there has been an increase in known colonies, there has been a considerable decrease in area of colonies on the island. Factors such as over-exploitation of muttonbirds in the past and grazing over colonies have now disappeared, but in their place have been left the introduced predator, the fox, and a potentially more important factor, human utilization of colony areas. It is concluded that the present island colonies are generally secure at a reduced level.