Between 1 January and 31 December, 2006, 34 consecutive cases of severe pre-eclampsia (12), imminent eclampsia (10) and eclampsia (12) who were admitted at the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife in the south-western part of Nigeria, were investigated for the development of HELLP (haemolysis, elevated liver enzymes and low platelet count) syndrome in a prospective study. The ages of the women ranged from 18 to 38 years, parity 0-5 and the estimated gestational age from 18-41 weeks at presentation. A total of 26 (76.5%) of the patients were unbooked, six (17.6%) of the 34 cases developed HELLP syndrome. Four (33%) of the 12 eclamptics developed HELLP syndrome, while only one (10%) of the cases of imminent eclampsia and 1 (8.3%) of severe pre-eclamptic cases developed the syndrome. Using the Mississippi Triple class system, none of the HELLP syndrome cases belonged to Class I; 4 were categorised in Class II while 2 were in Class III. All of the four eclamptic cases with HELLP syndrome died giving a 100% fatality rate while none of the imminent eclamptic and severe pre-eclamptic patients with the syndrome died. Furthermore, there were six (15.8%) perinatal deaths among the 38 infants delivered by the 34 mothers with severe pre-eclampsia/eclampsia. Our data suggest that the development of HELLP syndrome is more likely in eclamptic patients and when it occurs in them, it is highly fatal. Most of the cases in this study were unbooked. Substandard care may have contributed to the progression of the disease state and consequently, to maternal mortality. It is imperative to draw up an action plan for the identification of the risk factors for the development of pre-eclampsia/eclampsia at peripheral hospitals and maternity centres and for prompt referral of such cases afterwards. Efforts should also be geared towards the minimising of treatment delay in all phases, so as to minimise both perinatal and maternal morbidity and mortality.