Here we report, that mHSA, mBSA (bovine) and mMSA (mouse) bind to recombinant HIV-1 gp120 of the laboratory strain NL4-3. Binding of HOCl-modified serum albumins to gp120 also inhibited binding of recombinant CD4 (rCD4) and V3 loop-specific antibodies. All three HOCl-modified serum albumins inhibited viral infection and syncytium formation in a dose dependent manner.