Despite new comprehensive approach in diabetes care, type 1 diabetes is still facing considerable premature mortality. This study aims to examine associated risk factors for all-cause mortality among prevalent patients with type 1 diabetes mellitus (T1DM) within 5 years’ period and subsequently develop a logistic regression model to predict the outcome. This was a cohort study where prevalent patients diagnosed with T1DM were notified in a national diabetes registry. Patients’ particulars were recorded between 1 January 2009 and 31 December 2009. Their records were matched with national death record at the end of year 2013 to determine the status of mortality within 5 years. The factors associated with mortality were investigated, and a prognostic model was developed based on logistic regression model. There were 665 patients included in the study, and 105 patients died within 5 years. The mortality rate was 1.6 persons per 100 person-years and the standardized mortality ratio was 10.04. Majority causes of death were due to circulatory system (33.8%) and infection (32.5%). Multivariate analysis suggested that gender, age group, and ischemic heart disease (IHD) were the major contributing factors towards the outcome. Elderly male with IHD has a significant risk of mortality within 5 years with probability of event of 0.755, while elderly female with IHD has probability of event of 0.612. The main causes of death among prevalent T1DM patients were heart disease and infection. Male gender, elderly age group, and having IHD were significant risk factors of mortality in prevalent T1DM patients within 5 years.