In 1891 the Society assumed its present name when Queen Victoria granted permission to use the prefix Royal. Throughout the late 1890s and the post-Federation years, the Royal Agricultural Society of NSW cemented its position, introducing new competitions and expanding facilities. Increasingly, mining and secondary industries, technical innovators and commercial operators were encouraged to exhibit. As well, the Society showed renewed interest in education, partnering with the Government’s recently formed Department of Agriculture to put on lectures and displays.

Despite military occupation of the ground throughout WWI, the Show continued to be held. But in 1919 returning troops brought back the deadly Spanish influenza, prompting the Show’s cancellation that year as a public health measure. Temporary hospital wards and a morgue were set up on the Showground. When the crisis was over the RAS quickly regrouped, however, working closely with Government to reset the State’s post-war agricultural agenda. In the 1920s another parcel of land was added to the Showground, which had grown in area over the years. An ambitious building program began, and by the end of the 1930s all the iconic buildings of Moore Park were in situ. When the worst of the Great Depression was over attendances grew, and in 1938 an astonishing one million visitors poured through the gates for the first time. WWII broke out and the army took over the Showground again, vacating each Showtime until 1941. Ultimately, military needs took priority and the Show closed until the end of the war.