A two year randomised controlled trial of headgear in Rugby Union football is being conducted in Sydney, Australia. This paper gives an overview of this study in progress and presents results related to the development and laboratory performance of the headgear. The study commenced in 2002. Participants recruited to the study are in the under 13, 15, school open (U18) and colts age groups. There are three study arms: control, IRB-approved headgear, and modified headgear. The IRB approved headgear is a popular model in rugby, the Canterbury Honeycomb model manufactured by BodyArmour in New Zealand. The dimensions of this model were altered by increasing foam density and thickness to produce the modified headgear. In impact energy attenuation tests of 15 and 20 Joules onto a flat anvil, the modified headgear demonstrated average maximum headform accelerations of 23% and 33% of the standard model, respectively. Whether or not this improvement translates into reductions in injury will be determined by a comparison of the rates and severities of head injuries across study arms. Furthermore, these dimensional changes may not be acceptable to rugby players. Player attitudes towards safety and the use of protective clothing, injury history, experience and on-field behaviour will be examined via structured pre- and end of season surveys and analysis of match video.