Aim and objectives: To analyze the anatomical and functional single ventricle lesions receiving Fontan circulation and morbidity and mortality in patients who underwent surgery. Material and Methods : All data from Case records : Patient demographics, Diagnosis, Surgeries Performed, OT records, and follow up record collected and analyzed in excel spread sheet. Continuous data was presented as Mean and Standard Deviation, categorical data as percentages, between 2011 and 2020. Results: In this study, there are 20 patients in which most common diagnostic presentation in this study group is Tricuspid atresia with pulmonary stenosis. Mean age group at which the Fontan procedure was performed is 11 years (all the patients are above 4 years of age) with slight female predominance. All the patients showed increased haemoglobin and haematocrit values. All the patients are in sinus rhythm with good Ejection fraction with normal venous return. Among which 7 cases required cardiac arrest due to dense adhesions or distorted anatomy due to previous procedure. 2 cases among those 7 cases required circulatory arrest and 1 case died on POD 4 due to Low cardiac output syndrome and the other case recovered. Among 20 patients, 6 patients underwent Non-Fenestrated Extracardiac Fontan procedure and 14 patients underwent Fenestrated Extracardiac Fontan procedure, of which Fenestrated Fontan procedures were showed improved outcomes compared to Non-Fenestrated Fontan procedure. In this study group, 13 patients underwent primary closure and 7 patients underwent delayed closure. 3 patients underwent Re-exploration. In this study, 3 patients developed Renal impairment post-operatively with significant morbidity. There patients were managed with the peritoneal dialysis and gradual improvement was found in 2 patients and 1 patient died on POD 3. The mean ICD duration is 13.9 days. In this study group, all the cyanotic congenital heart conditions with low SpO2 showed improvement after the Fontan procedure. The Mean SpO2 in this study group is 94%. The overall survival rate of this study group is 75% with a mean follow-up period of 5.5 years. Conclusion : After Fontan completion procedure with good outcomes after Extra-cardiac Total cavo-pulmonary connection with ePTFE conduit. Patients need to be followed up for long term. The multidisciplinary approach is most beneficial in proving good outcomes. The increasing quantity of the adult Fontan patients creates challenges for adult.