The pattern of congenital chest wall malformations has been studied prospectively at the University of Ilorin Teaching Hospital between 1983 and 1987. A clinical series of 20 patients was found among 2195 patients selected randomly from 10,031 patients obtaining radiographs, and also from 1070 patients seen in the Cardiothoracic Surgery Clinic. An autopsy series of 15 foetuses and newborns was found among 205 studied for malformations. The 35 cases were found to have supernumerary ribs (10 clinical, eight autopsy), absent or defective ribs (three clinical, four autopsy), sternocostal deformities (three clinical, three autopsy) and four clinical cases with thoracic/thoraco-lumbar scoliosis and neonatal dwarfism with short ribs. Apart from two autopsy specimens (Cantrell's pentalogy with acrania and extensive abdominoperineal omphalocele) whose associated malformations appeared to be incompatible with life, all foetuses and newborns apparently had usual perinatal causes of death. One patient presented with costoclavicular syndrome while another had chest wall excision for a suspected tumour in a bifid rib. A patient with Poland's Syndrome and absent digits, and another infant with Cantrell's Syndrome are awaiting surgical reconstruction. The incidence of the malformations is approximately 1.01%. Other clinicopathological features are presented and the literature is reviewed.