Eleven gliomas were serially cultivated and examined for DNA distribution by flow cytometry and simultaneously for morphological features by light microscopy at the various passage levels until passage 50 at most. Seven gliomas (four low-grade gliomas, three anaplastic gliomas) showed a similar DNA distribution pattern with a main diploid and small tetraploid peaks at various passages. In this group, only one culture formed a permanent cell line, whereas six cultures showed a limited growth ranging from 6 to 24 passages. In contrast, the other four gliomas (each an anaplastic glioma) showed a marked change of DNA distribution through passages and finally a single DNA aneuploid population prospered. Each of these four gliomas yielded established cell lines. Thus, it is suggested that the change of DNA ploidy and prosperity of DNA aneuploid populations in flow cytometry might be used as early and reliable indices for the later establishment of glioma-derived permanent cell lines. Since the changes of DNA distribution are frequently associated with the morphological changes, as seen in the latter group, careful tracing of morphological features is valuable in determining of the fate of cultures, especially in the absence of a flow cytometer. The correlation between the potential to become established cell lines and histology of the original gliomas is also discussed.