Purpose: The aim of this study was to investigate and compare the marginal fit of posterior fixed dental prostheses (FDPs) made of monolithic and veneered computer-aided design/ computer-assisted manufacture (CAD/CAM) zirconia ceramic with metal-ceramic posterior FDPs. Materials and Methods: Thirty standardized steel dies were prepared to receive posterior three-unit FPDs. Specimens were randomly divided into three groups (n = 10): (1) metal-ceramic (control group), (2) veneered zirconia, and (3) monolithic zirconia. All FDPs were cemented using a glass-ionomer cement. The specimens were subjected to thermal cycling (5°C to 55°C). A scanning electron microscope (SEM) with a magnification of ×500 was used for measurements. The data were statistically analyzed using one-way analysis of variance and paired t test. Results: Both zirconia groups showed similar vertical marginal discrepancies, and no significant differences (P = .661) in marginal adaptation were observed among the groups. No differences were observed in either group in marginal discrepancies between surfaces or abutments. Conclusion: Monolithic zirconia posterior FDPs exhibit similar vertical marginal discrepancies to veneered zirconia posterior FDPs. No influence of localization measurements was observed.