Wait time is among the most commonly cited barriers to access among individuals seeking entry to substance abuse treatment, yet relatively little is known about what contributes to it.To address this gap, this study draws from a national sample of substance abuse treatment clients and programs to estimate the proportion of clients entering treatment who waited more than 1 month to receive it (outpatient, residential, or methadone) and to identify client and program characteristics associated with wait time. This study used data from the National Treatment Improvement Evaluation Study (1992-1997). The data include 2920 clients from 57 substance abuse treatment programs. Generalized linear modeling was used to identify client and program characteristics associated with wait time to treatment entry. Results of modeling indicate that being African-American (OR: 1.40; CI: 1.04, 1.88), being referred by criminal justice (OR: 1.70; CI: 1.18, 2.43), and receiving methadone (OR: 3.90; CI: 1.00, 15.16) were associated with increased odds of waiting more than 1 month. Conversely, having a diagnosis of HIV/AIDS (OR: 0.38; CI: 0.19, 0.77) was associated with decreased odds of waiting for more than 1 month. A significant proportion of clients waited more than 1 month on enter treatment. Greater odds of such wait times were associated with being African-American, criminal justice-referred, and receiving methadone.