Indigenous prison populations grew faster than non-indigenous prison populations over the period. Nationally, the number of indigenous prisoners increased by an average of 6.9 percent a year, 1.7 times the average annual growth of the non-indigenous prison population. Indigenous people were more likely than non-indigenous people to be in prison, although the rate of indigenous overrepresentation declined from 14.2 percent in 1988 to 11 percent in 1998. No differences were noted between the gender composition of indigenous and non-indigenous prison populations, with males constituting 95 percent of both prison populations. The median age of both indigenous and non-indigenous prison populations increased during the period, from 28.3 years in 1988 to 30.8 years in 1998. Both indigenous and non-indigenous prisoners were on average younger than the population of imprisonable age. The age distribution of indigenous prisoners was more skewed toward the younger age groups than that for non-indigenous prisoners. With regard to offense, the percentage of indigenous prisoners sentenced for assault increased by 6.8 percent over the period, whereas the percentage sentenced for robbery increased by 3.1 percent. On the other hand, the percentage of indigenous prisoners sentenced for theft declined by 5.4 percent. While non-indigenous prisoners experienced a 6-month decline in sentence length between 1988 and 1998, the median decline for indigenous prisoners was only 3 months. Implications of the findings are discussed in terms of indigenous prison population characteristics and overrepresentation in the Australian criminal justice system. 8 references, 2 tables, and 5 figures