||The commonly used renal replacement therapy for the end stage renal disease (ESRD) is the maintenance dialysis and kidney transplantation. The objective of the study was to evaluate and determine the frequency of different complications during and after haemodylisis in patients having ESRD. A patient having approaches for the renal transplantation is the gold standard of treatment. The maintenance haemodialysis is the substitute for the proper kidney functions. On one hand, it is blessing for renal failure patients, while on other hand, complications may occurs during and after the process of hemodialysis. Some are inherent side effects of the normal extra corporeal circuit, some results from technical errors, & yet others are due to abnormal reactions during the dialysis procedure. This prospective and observational study was conducted at two different public and private hospitals of Karachi, Pakistan. Patients were selected from the lists of regular hemodialysis patients during the period of August, 2011 to April, 2012. The most frequently observed complications were cardiovascular system (CVS). These complications like hypotension & arrhythmia were at the top with frequency of 79.3%. The gastrointestinal (GIT) complications like nausea, vomiting abdominal pain followed the CVS complication in order of frequency. There is a need for development of effective strategies to prevent gastrointestinal bleeding in patients on hemodialysis who use Nonsteroidal anti-inflammatory drugs (NSAIDs). These complications may be decreased by taking some measures such as premedication of hemodialysis, well trained dialysis machine operators, latest technology dialysis machines, full monitoring during the process of dialysis and to improve the socioeconomic conditions of the patients so as to reduce the post dialysis problems such as infections at the site of catheter.