Objectives: The aim of this study was to evaluate the bond strength of different direct reliners to acrylic resin for denture base. Materials and methods: Double-cone specimens were made: HA-heat-cured acrylic resin-(n = 20); U-Ufi Gel Hard C-(n = 10); K: Kooliner-(n = 10); R-Rebase II Fast-(n = 10) and RH-Rebase II Fast + Resin Hardener-(n = 10). Ten HA samples were immediately submitted to cohesive test. The remaining HA samples and others were submitted to thermal aging (HAaged, 1000 cycles,

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... 5-55ºC), followed by tensile test. For tensile strength, 50 single cone-shaped samples were made of heat-cured acrylic resin and aged (HAaged, 1000 cycles, 5-55ºC). After surface treatment, relining resin cones were build up using silicon molds, and stressed to failure. Values of cohesive and tensile strength were submitted to one-way ANOVA and Tukey's test (α = 5%). Results : Bond strength were: HA/HAaged: 21.17 (±4.89)a, U/HAaged: 11.56 (±1.98)b, R/HAaged: 9.69 (±2.37)b, RH/ HAaged: 9.38 (±1.78)bc and K/HAaged: 5.98 (±1.90)c. The cohesive strength were: KCoe: 22.29(±4.06)a; RCoe: 23.99 (±3.29)a; RHCoe: 24.84 (±3.88)a; UCoe: 25.62 (±3.03)a; HAaged: 36.06 (±8.65)b and HA:42.29 (±7.68)b. Groups followed by the same letters do not show differences. Conclusion: Bond strength of acrylic resin to acrylic denture base material is higher than the reliners and Ufi Gel Hard C showed the higher bond strength.