The aim of this in vitro study was to compare the fatigue resistance of three kinds of heat-polymerized acrylic resins (conventional heat-polymerized, rapid heat-polymerized, high impact acrylic resin), a kind of visible light-cured resin and a kind of self-cured acrylic resin. A total of 60 notched and un-notched specimens (65 mm x 10 mm x 3 mm) were fabricated, 12 from each material. The fatigue resistance was measured by applying repeated three-point bending deflection to the specimens. For statistical analysis, Kruskal-Wallis test followed by Dunn's multiple comparison tests were used. The Kruskal-Wallis test revealed significant differences in the fatigue resistance among some groups (p < 0.05). Conventional- and rapid-heat polymerized resins had lower fatigue resistance values than heat-polymerized high impact acrylic resin, but the differences were statistically nonsignificant according to Dunn's test (p > 0.05). High impact acrylic resin was also found to have significantly higher fatigue resistance value than that of self-cured resin and light-cured resin (p < 0.05). Further, there was no statistically significant difference between the mean fatigue resistance value of visible light-cured resin and self-cured resin (p > 0.05). (C) 2010 Elsevier Ltd. All rights reserved.