Over 132,783 newborns from 1981-1995 have been analysed revealing 267 infants with cleft lip and/or palate resulting in a mean frequency of clefts at 2:1000. Additionally, the forms and sides of clefts, and sex of the children with clefts have been defined. The comparison of the studies in Lodz from 1951-65 and 1981-95 indicates a slight increase in the occurrence of clefts.