In the sample of prisoners returning to Chicago (n=400), there was little evidence of substance-abuse treatment matching with inmate need. Nearly half of those with a preprison drug problem failed to receive needed treatment either in prison or after release, and only 14 percent received the continuous treatment suggested by research as being most effective in preventing relapse and recidivism. Virtually the same proportion of prisoners received substance-abuse treatment (42-43 percent) in prison regardless of whether they reported having a drug problem. Data on continuity of substance-abuse treatment after release shows that, without regard to actually reporting a drug problem, only 24 percent of those who received inprison treatment received postprison treatment as well. For those who reported a drug problem when entering prison and who received inprison treatment, 32 percent also received treatment after release. If those whose only treatment after release was participation in Alcoholics Anonymous or Narcotics Anonymous are not considered in the analysis, only 7 percent of those who received any inprison treatment and only 9 percent of those with an acknowledged preprison drug problem who received inprison treatment also received treatment after release. Reasons for this lack of inmate-treatment matching include lack of routine administration of screening instruments, failure to assign and manage inmates for treatment in accordance with screening information, and the lack of incentives for inmates to choose inprison programs that match their actual needs. This report recommends several mechanisms that can improve inprison and postrelease inmate-treatment matching for those with substance abuse problems. 1 figure, 5 notes, 20 references, and appended description of study methodology