A family with autosomal dominant inheritance of sacral agenesis is described. Ten members were affected; four had associated presacral teratomas and anterior sacral meningoceles, giving rise to serious complications in three, including bacterial meningitis, local recurrence of teratoma and perianal sepsis. Three of those with presacral masses presented initially with anorectal anomalies. Other associated abnormalities included tethering of the cord, hydrocephalus, duplex ureter, hydronephrosis, vesicoureteric reflux, neurogenic bladder, bicornuate uterus, rectovaginal fistula and hereditary spherocytosis. Early diagnosis and surgical excision of a presacral mass is advised to prevent future morbidity and mortality.