This study examined treatment access and outcomes for persons placed on drug abuse treatment waiting lists. Participants (n = 170) were recruited when they entered either a methadone detoxification program or a day treatment program, and were waiting for methadone maintenance or residential treatment, respectively. Participants were interviewed at baseline and 2-months follow-up. Excluding the index treatment episode, 73% received some treatment during the follow-up period. Mixed effects regression was used to compare short-term outcomes for clients who did and did not enter treatment following the index episode. We found increased drug problems, over time, for all participants. Those enrolled in treatment at follow-up reported higher employment problems (collapsed across time) compared with those not in treatment. Last, participants enrolled in any subsequent treatment showed a decrease in psychiatric problems over time, while those not enrolled in subsequent treatment showed an increase in psychiatric problems. Participants who entered treatment within 60 days after being placed on a waiting list showed improvement on psychiatric measures but not on substance abuse measures.