During the period January 1994 to December 1999, a total of 395 patients--adults and children--underwent various types of open heart surgical (OHS) procedures. The age range of these patients was 10 days to 77 years. Most (43.5%) of these patients underwent valve replacement--first time and 'redo'--as a result of rheumatic heart disease of varying duration and severity. The other large group was the complex congenital heart abnormalities (16%), followed by the group that underwent repair of atrial septal defect (13%), coronary artery bypass graft (13%) and repair of ventricular septal defect (12%). Open valve repair (2%) and excision of atrial myxoma (0.5%) were uncommon OHS procedures. Nine patients (2.3%) developed severe neurological complications (NCs) post-OHS. These included: a short period (< 48 hours) of irritability and fluctuating consciousness level; seizure activity associated with hemisparesis and/or blindness; severe encephalopathy and vegetative state. Four patients showed complete recovery, but one died as a result of complications of the anti-seizure medication. Of the other five, four died as a result of the NCs, and one was discharged in a vegetative state. Such severe neurological complications after an otherwise successful cardiac surgery represent a devastating outcome for patients and their families, and the social and economic impacts are enormous. Several risk factors were identified. The main ones being mitral valve replacement (MVR), especially 'redo' surgery, female gender, age over 60 years, high New York Heart Association functional class and post-operative hypotension. However, the true incidence of NCs (gross and subtle) in the study group cannot be ascertained. A detailed, structured neurological and neuropsychiatric assessment, both pre- and post-operatively, is therefore needed to document the true incidence of this complication. There is also the need for public education, especially for those with valvular disease, in order to encourage changes in attitude and behaviour towards continued follow-up care and valve surgery, both first time and 'redo'.