OBJECTIVE 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. METHODS Thirty standardized steel dies were prepared to receive posterior three-unit FDPs. 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. CONCLUSIONS Monolithic zirconia posterior FDPs exhibit similar vertical marginal discrepancies to veneered zirconia posterior FDPs. No influence of localization measurements was observed.