Cultured human cells were established from various organs of a congenitally abnormal fetus. The life span of lung cells was equivalent to 62 PDN, but those of cells from skin, liver, bone marrow and kidney were very short. Chromosome analysis of cells derived from the lung and skin showed few aberrations, but aneuploid cells and chromosomal aberrations were frequent in the kidney cells. There was no difference in UV sensitivity between lung cells and kidney cells; both were about twice as sensitive as normal human fibroblasts. There was no correlation between the UV sensitivity and the length of life span in vitro, the amount of chromosomal aberrations or tissue origin of the cells.