The creep behavior of hot-pressed Si3N4 ceramics was investigated. The proposal of this work is to investigate the use of yttrium-rare earth oxide mixture, CRE2O3, produced at FAENQUIL, as sintering additive, since the cost of production of this material is 80% inferior to Y2O3. These ceramics were obtained by uniaxial hot-pressing using different additive contents and mixtures (CRE2O3-Al2O3 or CRE2O3-AlN). Compressive creep tests were carried out at 1300 degrees C and 300 MPa, in air. The Si3N4-CRE2O3-Al2O3 ceramics demonstrated that the creep resistance is inversely proportional to the additive content. Mixtures with high intergranular phase content presented low creep resistance due to high oxidation and more pronounced softening of the intergranular phase. Si3N4-CRE2O3-AlN ceramics demonstrated better creep resistance with a steady-state creep rate of 7 x 10(-8) s(-1). This behavior is related to the alpha-SiAlON content, a solid solution of Si-3 that incorporates a great fraction of intergranular phase, decreasing the amount of intergranular phase.