Indian studies on the prevalence rates of substance use and substance use disorders in patients of Schizophrenia are scarce. The present study was planned to find out the prevalence, type, frequency and pattern of substance use in patients of Schizophrenia with substance use disorders and further to evaluate the effect of substance use on various socio-demographic variables. This cross sectional study was undertaken in Department of Psychiatry in a tertiary teaching hospital with an attached medical college from 2011 to 2013. The sample consisted of 100 patients diagnosed as Schizophrenia with substance use disorders using the Diagnostic and statistical manual – IV Text Revision (DSM-IV-TR) attending the Psychiatry Outpatient department or those admitted in the Psychiatry ward. The prevalence of substance use disorders in patients of Schizophrenia was found to be 51%. Nicotine was the commonest substance to be consumed, followed by cannabis, alcohol and opioids. Cannabis dependence was the commonest DSM diagnosis. Substance use disorders are more prevalent in young male, unmarried, unemployed patients living in rural areas and in joint families. More prevalence of substance use disorders was found in patients having a family history of schizophrenia, or those who consume higher number of substances or as and when required/ multiple times a day. Since the symptomatology and clinical outcome of the illness is adversely affected by presence of substance use, it becomes important to screen, detect, and treat these comorbid disorders. This would definitely improve the clinical outcome, quality of life and cut down treatment costs to a considerable extent