INTRODUCTION: The wrist of the human called carpus, has eight bones which are ordered in two equal rows. In some people, the numbers of these bones are congenitally more or fewer than eight. When in the process of osteogenesis, two of these bones tobe fused together, the number of the wrist bones becomes seven. The goal of this studyis to determine the prevalence of congenital lunato- triquetral bone in the wrist of human being.MATERIALS & METHODS: This was a descriptive study. The healthy adult from both sexes, referred to the hospitals in Ahwaz were randomly selected and their wrists were .examined by radiography. They was between 18 to 57 years old. The total numbers of the wrists were 2440, from which 1474 cases belonged to the males and 966 cases to the females.RESULTS: The prevalence of the congenitallunato-triquetral bone was 0.12%. This variation was not seen in women at all; in the men, it was both bilateral and unilateral.CONCLOUSIONS: There was no significant difference in prevalence of this congenital variety among Iranian, American and Japanian communities while there were significant differences between them with Ghana, Nigeria, and eastern Africa.