Fifty-two permanent tooth pairs of 37 children aged 8 to 16 years were evaluated for opacities and hypoplasia of the enamel. Formocresol pulpotomy had been performed in one of the primary teeth proceeding each tooth pair. The study comprised teeth with clinically and radiographically successful and unsuccessful pulpotomies. None of primary control teeth had a history of pulp exposure. 57 permanent teeth with caries-free predecessors were included for further control.In the formocresol treated group the prevalence of opacities according to localization was: occlusal surface 25%, buccal surface 37% and palatal surface 14%. In the control group, the corresponding prevalence was 21%, 35% and 14%. The prevalence of hypoplasia was 2%, 8% and 0% respectively, in the formocresol group and 2%, 14% and 4% in the control group. In the 57 permanent teeth opacities were found in 16% of the occlusal and buccal surfaces and in 18% of the palatal surfaces. The prevalence of hypoplasia was 12%, 5% and 0% respectively.No differences in prevalence of enamel defects on permanent teeth could be demonstrated in relation to child age when formocresol pulpotomy was performed.The conclusion of the study was that no relationship between formocresol pulpotomy of primary teeth and enamel defects on their permanent successors could be demonstrated.