This study compared the shear bond strength (SBS) to enamel of five self-etching primer/adhesive systems and one total-etch, one-bottle adhesive system. Sixty freshly extracted bovine incisors were mounted, polished to 600-grit and randomly assigned to six groups (n=10): Adper Prompt Self-Etch (AD), OptiBond Solo Plus Self-Etch (OP), AdheSE (AS), Tyrian (TY) and Clearfil SE Bond (SE) as self-etching systems; and Single Bond (SB) as a total-etch system (control). The respective hybrid composite was applied in a #5 gelatin capsule and light-cured. After 500 thermal cycles (5 degrees C-55 degrees C), the specimens were loaded in shear using an Instron at 5 mm/minute. Mean bond strengths were analyzed with one-way ANOVA, followed by a Duncan's post-hoc test (p 0.05). SBS (mean +/- SD) were: AD=13.0(+/- 2.5); OP=5.6(+/-2.3);AS=12.6(+/-3.7); TY=7.6(+/-2.6); SE=17.6(+/-4.5) and SB=17.9(+/-4.4). ANOVA showed a significant difference at p<0.0001. Duncan's post-hoc test ranked this difference in three homogeneous subsets. Only SE showed similar enamel SBS compared to the total-etch system tested (SB). AD and AS were ranked in the intermediary Duncan's subset, while TY and OP resulted in the lowest SBS. SBS to enamel with self-etching primers may depend on its specific composition.