Abstract: Pyrrolidine compounds of Formula I: (wherein R1, R2, R3, R4, R5, R6, R7, R8a, R8b, j, k, 1, m, and n are defined herein) are described. The compounds are modulators of CCR5 chemokine receptor activity. The compounds are useful, for example, in the prevention or treatment of infection by HIV and the treatment of AIDS, as compounds or pharmaceutically acceptable salts, or as ingredients in pharmaceutical compositions, optionally in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.