Changes in the characteristics of rabbit lens epithelial cells during long-term cultivation were examined. From the beginning of cultivation to the 24th generation, the cells grew exponentially, and then the growth stopped. This growth-arrested period lasted for 60 days, and then they grew exponentially again. The cells had a cobblestone-like appearance through the whole cultivation period except in the growth-arrested period. In an immunofluorescence examination with a monoclonal antibody against alpha-crystallin, all of the primary cells and the cells in the 20th generation showed specific fluorescence to alpha-crystallin throughout their cytoplasm. However, some of the cells in the 24th generation did not show this fluorescence, and all of the cells in the 35th and 70th generations showed fluorescence only around the nuclei and none in the cytoplasm. The primary cells and the cells in the 20th generation were capable of forming lentoid bodies, but the cells after the 24th generation were not. These results indicate that some of the characteristics of the rabbit lens epithelial cells are lost during the growth-arrested period.