Early detection and intervention for alcohol problems have been shown to reduce subsequent health consequences. However, the extent to which these practices have been implemented is unclear. The study assessed among hospital in-patients (1) the prevalence of at-risk drinking and smoking, (2) current practice in detection and intervention for at-risk drinking and smoking and (3) self-reported effect of any intervention. A brief self-administered questionnaire was administered to adult in-patients addressing alcohol use [Alcohol Use Disorders Identification Test (AUDIT) questionnaire], smoking and self-reported effect of any recent intervention for drinking or smoking. The participant's smoking status and alcohol use as recorded by medical and nursing staff was compared to self-reports. Of 448 in-patients, 50% (226) participated in the study; 38% (170) were ineligible and 12% (52) refused. Participants were aged 61.3 (±18.9) years. A higher number of problem drinkers (11.9% vs. 3.5%, p < 0.0001) and current smokers (17.3% vs. 9.3%, p < 0.0001) were identified by the questionnaire compared to the medical records. Hospital staff quantified smoking more consistently than alcohol (54% vs. 42%, p = 0.02). Of those who recalled an intervention, 19% of drinkers and 27% of smokers said they had stopped drinking or smoking for a period since that intervention. Further improvement is required in the rates of detection and interventions for alcohol use disorders and smoking in the hospital setting.