If you don't have 3 button mouse you can select edge loops by holding Shift + Alt + Right Mouse Click

Hold down shift + alt + right mouse click

  • Dwayne Savage(dillenbata3) replied

    It is easier to use shift+Double click or Double click.

  • Rob Reid(rob221) replied

    At least as of Blender version 3.0.0, you can also double-left-click to select edge loops (and face loops if you are in face select mode).