Homo- and heterochiral poly(mandelic acid)s (PMDAs) were synthesized under strongly acidic, mildly acidic, and nonacidic conditions. The water-soluble fractions of these polymers were evaluated with respect to their inhibitory activity against the human immunodeficiency virus (HIV-1). Polymers were prepared via a step-growth mechanism, yielding linear polyesters. The polymers were characterized by CHS elemental microanalysis, X-ray fluorescence (XRF), and FT-IR spectroscopy. Polymers prepared by the three methods have different structures. Both elemental microanalysis and XRF indicated the presence of S in those polymers prepared by treatment with concentrated H2SO4, which were the only ones exhibiting inhibitory and virucidal activity against HIV-1, mediated by their binding to cellular co-receptor binding sites on the virus envelope glycoprotein gp120. Additionally, FT-IR spectroscopy indicated the complete absence of C=O functionality in the H2SO4-prepared PMDA.