According to the Australian census figures, the Baptists reached their peak in terms of percentage of the population in 1901 when they constituted close to 2.4 per cent of the population. However, after declining to 1.6 per cent in 1933, the proportion of the population identifying as Baptist has not changed greatly since that time. However, the actual number of people identifying themselves as Baptist has risen almost every census reaching almost 310 000 in 2001 or 1.7 per cent of the population.

In 1954 there was a small dip in the number of Baptists. This could have represented a real decline in adherence in Baptist churches, which was reversed, to some extent in the later fifties and sixties. The Billy Graham crusade of 1959 and other evangelistic crusades around those times had a significant impact on Baptist numbers. Immigration of British migrants in the 1950s and 1960s also had an affect on Baptist numbers.

While some other denominations have seen considerable decline, the Baptists have grown at a similar rate to the population over recent years. The Baptist age profile is a likely factor in this as it more closely resembled that of the population at a time when most other Protestant denominations are over-represented by those aged over 40 years.