The present study aimed to compare post-aging microtensile values of fissure sealant(FS) containing amorphous calcium phosphate(ACP) with or without bonding after various enamel-etching methods. The buccal enamel surfaces of teeth were prepared and divided into five main group according to enamel etching (Group 1; acid-etching, Group 2; air-abrasion, Group 3; 2W, Group 4; 3W, and Group 5; 4W of Er:YAG laser). Each main group was subdivided as with(Subgroup B) or without(Subgroup A) a bonding system. We applied FS-containing ACP to etched enamel surfaces. All specimens were aged by Thermocycling and water bath. We then measured microtensile bond strengths and analyzed data with two-way ANOVA and Tukey's tests. We found a statistically significant difference between Group 1 and Group 2, between Subgroup B of Group 5 and Subgroups B of all other groups, and between Subgroups A and Subgroups B of all main groups (p<0.01). Er:YAG laser-etching may be an alternative enamel etching method to acid-etching for ACP-containing FS.