In the present study, the effects of 660 and 810nm diode laser on the proliferation and invasion of cancer cells were investigated. Sixteen plates of oral cancer cells originated from tongue SCC were irradiated with diode laser at 660nm (40 and 80mW) and 810nm (100 and 200mW) with the energy density of 4Jcm-2 . One plate received no irradiation (the control). Irradiation was performed at four times (0, 24, 72 and 168h). Cell proliferation was measured by MTT assay. The Ki67 and vascular endothelial growth factor (VEGF) markers were examined by real-time polymerase chain reaction (RT-PCR). Cyclin D1, E-cadherin, β-catenin and matrix metalloproteinase-9 (MMP-9; flow cytometry) were also evaluated. Proliferation was lower in the irradiated groups. This result was significant for all groups at 24h. The percentages of cyclin D1 and MMP-9 were higher in 810nm groups, β-catenin and E-cadherin were higher in 660nm groups, VEGF marker was significantly lower in 810nm/200mW group, and Ki67 marker has no difference between the groups. According to the results of this study, laser irradiation at 0 and 24h resulted in a significant inhibitory effect on cell proliferation especially in 660nm/80mW and 810nm/200mW. Further studies are needed in this respect.