Our earlier studies showed that the apoptosis of renal tubules can be induced by sodium fluoride (NaF). The present study was designed to estimated the effects of B-cell lymphoma/leukemia 2 (Bcl-2), Bcl-2-associated protein X (Bax), and osteopontin (OPN) on the apoptosis of renal tubular cells induced by NaF at different levels. The technique of reverse transcription-polymerase chain reaction and densitometer scanning volume density were used to evaluate the changes of Bcl-2, Bax, and OPN mRNA in tubular cells treated with different doses of NaF (0, 1, 5, 7.5, 12.5 mgF-/L) for 48 h. Compared to control, the level of Bax mRNA significantly increased at cells of the 7.5- and 12.5-mg F-/L groups and the expression of Bcl-2 mRNA obviously decreased at cells of the 5- and 7.5-mg F-/L groups. The NaF also enhanced the expression of OPN mRNA in a dose-dependent manner, but the strongest expression of OPN mRNA was observed at cells of the 7.5-mg F-/L group. The results suggested that NaF induces the apoptosis in renal tubules via activation of the Bax expression and Bcl-2 suppression; OPN probably acts as protective role against apoptosis in fluoride-treated renal cells.