We succeeded in primary culture of 3 in 4 cases of glioblastomas. The long-term passage cultures were not done from the primary cultures of original tumor, but glioblastoma cell line (HUBT-n) was established from a xenograft of nude mouse. This line grew well without interruption for 4 years and was subcultivated over 120 times. The cells were spindle like or round in shape and neoplastic and pleomorphic features contained glial fibrillar acid protein (GFAP) and S-100 protein and grew multilayering without contact inhibition. A bough-shaped long projection was noted from a small cell. One of the characteristics of the HUBT-n cells was existence of well developed intermediate filaments in their cytoplasm. The cells proliferated rapidly, and the population doubling time was about 32 hours. The chromosome number showed a narrow distribution of diploid range. Abnormal constitution was observed in all cells by G-band karyotyping. The culture cells were easily transplanted into the subcutis of nude mouse and produced the tumor resembling the original tumor.