Engagement into treatment is crucial for improving outcomes among patients with substance use disorders. This study aimed to find the rates and characteristics of treatment noncompletion in patients who were admitted to a drug dependence treatment center in north India. This retrospective record review analyzed data from consecutive patients admitted between January 1, 2014, and December 31, 2014, at the National Drug Dependence Treatment Centre, Ghaziabad, India. The type of discharge was discerned from the records, along with selected demographic and clinical characteristics of the patient. A total of 942 in‑patients were included in the analysis, 936 (99.4%) of whom were males. The mean duration of ward stay was 12.7 (±8.1) days. Of the 942 patients, 779 (82.7%) completed the inpatient treatment while 163 (17.3%) did not complete (n= 95, 10.1% were discharged against medical advice; n= 44, 4.7% were discharged on disciplinary grounds and n= 24, 2.5% absconded or left without intimation). The inpatient treatment noncompleters had a shorter duration of ward stay (8.3±6.9 days vs. 13.6±8.0 days, P< 0.001), were of a greater average age (33.1±10.0 years vs. 30.5±9.4 years, P= 0.002), were more likely to be dependent on opioids (71.2% vs. 59.1%, P= 0.004) and less likely to be dependent on alcohol (30.1% vs. 42.9%, P= 0.002) than treatment completers. Understanding the characteristics of patients with substance use disorders who do not complete inpatient treatment may help in identifying those at‑risk of having poor outcomes. Efforts are required to address their concerns so that the overall patient outcomes can be improved.