This present study had three aims: 1) to evaluate the bond strengths of carboxylate and resin cements in cementing cast Co-Cr crowns to pretreatment of composite resin cores with eugenol and non-eugenol containing temporary cements, 2) to determine the microhardness of composite resin treated with temporary cement, 3) to view the surface differences of composite resin with SEM. The composite cores were divided into three experimental groups for the following pretreatments: Group 1, No treatment was provided, Group 2, The external walls of the composite cores were covered with eugenol-containing temporary cement, Group 3, The external walls of the composite cores were covered with non-eugenol containing temporary cement. Analysis of variance results showed that there was a significant difference between all three groups. Temporary cement with eugenol was significantly reduced the bond strength of full crown casting with resin cement compared with non-eugenol. The resin specimens treated with the eugenol-containing temporary cement showed the lowest microhardness values, the non-eugenol-containing temporary cement was not significantly different from those of the control groups.