PURPOSE: This study was designed to investigate and compare in vitro survivin activity in normal human os-teoblast and MG-63 osteosarcoma cell cultures with and without vitamin D3. METHODS: Normal human alveolar bone explants were recovered from extraction sites of non-carious teeth of 9 healthy donors and cultured to the 2nd passage. MG-63 osteosarcoma cells were obtained from ATCC. To compare the survivin activities in these two types of cells and to determine the effect of vitamin D3 on survivin expression and associated activities of cell proliferation and differentiation, levels of survivin, osteocalcin and alkaline phosphatase were measured at 7-20 day cultures with and without vitamin D3 in both cultures of normal osteoblasts and osteosarcoma cells. Matched pair t-test and two sample independent t-test were applied for statistical analysis of the data. P values of 0.05 or less were considered statistically significant. RESULTS: A significantly higher level of survivin was detected in normal osteoblasts compared to osteosarcoma cells at 7 days without vitamin D3 treatment (P<0.01). Survivin expression in normal osteoblasts significantly decreased after vitamin D3 treatment at 7 days (P<0.05), but not at 20 days of culture (P=NS), compared to that in normal osteoblast culture without vitamin D3 treatment. Vitamin D3 had no effect on survivin expression in osteosarcoma cells at 7 or 20 days (P=NS). CONCLUSIONS: Expression of survivin in cultured normal human osteoblasts and osteosarcoma cells was positively identified. There is a positive correlation between higher expression of survivin and less differentiated osteoblasts that still retain their proliferative ability. Vitamin D3 has significant negative effect on expression of survivin in normal human osteoblasts but not on that in osteosarcoma cells.