Suicidality is more commonly reported among individuals with addictions relative to the general population, though data from Asian countries remain scarce. The medical records of 2187 Singaporean patients with drug (n=879), alcohol (n=754) or gambling (n=554) disorders entering an outpatient treatment service were examined to explore differences in suicidal ideation and lifetime attempts between substance and gambling addictions. The relationship between suicidality, co-morbidity and addiction severity were also examined. 25.0% reported thoughts of suicide in the past month, 11.8% had a suicide plan and 12.2% reported lifetime attempts. Rates of suicidal ideation (thoughts, and plan) but not lifetime attempts were significantly higher among gambling than substance use patients. Co-morbid (DSM-IV axis-1) disorders were found among 32.5%, 38% and 40% of those reporting thoughts, plan and lifetime attempts respectively. Addiction severity was higher and quality of life lower among those reporting suicidal behaviors. Logistic regression revealed co-morbidity, debt, gender (being female) and being a gambling patient as significant predictors of suicidal behaviors. The findings highlight the importance of screening for suicidality, even in the absence of co-morbidity, particularly among gambling disorder patients with debts. Suicide risk should be assessed periodically and referral to suicidal prevention interventions routinely offered to this vulnerable population.