${gamma}$ -Tubulin is an essential component involved in microtubule nucleation. The present work examined whether the fast proliferation of cancer cells can be retarded by the depletion of ${gamma}$ -tubulin expression. Two different gastric cancer cell lines and one control cell line were treated with antisence oligonucleotides complementary to the messenger RNA of ${gamma}$ -tubulin. The$[^3H]$ -thymidine incorporation in the two gastric cancer cell lines, SNU-1 and SNU-216, was dramatically reducd by treatment with the ${gamma}$ -tubulin antisense oligonucleotides in a dosage-dependent manner. In contrast, the control cell line, NIH/3T3, showed no significant effect from the antisense oligonucleotides even at a high concentration. The ablation of ${gamma}$ -tubulin expression in the tumor cells resulted in an altered DNA synthesis during mitosis and it decreased the cell progression. Accordingly, the use of antisense oligonucleotides may be an effective way of inhibiting the proliferation of human gastric cancers.