BackgroundDiphtheria is a respiratory infectious disease of childhood. It is a fatal disease and may cause complications if not recognized early and treated properly. Despite availability of effective vaccination it continues to be reported from many parts of the world particularly developing countries. ObjectiveTo assess the demographic and clinical characteristics of diphtheria patients, and the predictors of outcomes of respiratory diphtheria. MethodsA prospective analysis of 180 patients with a clinical diagnosis of respiratory diphtheria admitted from 2011 to 2014 at a tertiary referral hospital. They were evaluated with respect to demographic details, immunization status, clinical features, complications and outcomes. ResultsMost common age group affected was children less than 5 years of age (87 cases, 48.33%). The peak incidence of diphtheria was seen in the months of September and October (111 cases, 62%). Majority of the patients were unimmunized (54%), followed by partially immunized (21%). The most common complication was respiratory in 80 cases (44%), followed by cardiac complications in 54 cases (30%), and renal (16%) and neurological complications (10%). Cardiac complications were associated with the highest mortality rate (63%). The presence of bull neck and pseudomembrane score >2 was associated with a high mortality. ConclusionDiphtheria is still a preventable public health problem in many developing countries. Improved vaccination coverage, including booster dosage, coupled with early detection and effective treatment, may all reduce incidence and mortality.