In this in vitro study, the cytotoxicity of metal-ceramic dental casting alloys containing high gold, chrome-cobalt, chrome-nickel, and titanium was examined on the African Green Monkey Kidney cell culture. Toxic behaviours of the metal casting samples were evaluated by the Agar and filter diffusion testing methods. Totally 48 sample disks (from each metal alloy 12 samples) were prepared in 3 mm diameter and 2 mm thickness. Vero fibroblast cells were used for both of the testing methods. As a positive control, 1M ammonium molybdate solution absorbed sterile blotting paper, and as a negative control, sterile distilled water absorbed sterile blotting paper in the same diameter with the samples were used. To determine the cellular toxicity, microscopic and macroscopic controls were performed corresponding to the 24th, 48th, 72nd, 96th, and 120th hours of the testing methods. The cytotoxic response in the agar and filter diffusion tests were evaluated macroscopically by the zone index developed according to the size of the decolourised zone and microscopically by the number of cells in the region of cell lysis. In order to confirm the results, the agar and the membrane filter removed cells were fixed with 3% formalin for a period of 1 hour. Cells, after dried with a blotting paper, were painted with 0.35% crystal violet and examined in the Inverted Tissue Culture Microscope. None of the samples of metal casting alloys had shown any cytotoxicity effect during the agar and filter diffusion testing. However, 100% toxicity was observed in the cells in the region of 1M ammonium molybdate solution absorbed blotting paper samples (positive control).