This work is devoted to the study of the physicochemical properties of the water-soluble adduct fullerene C60-l-methionine. The adduct was characterized using13C solid-state NMR spectroscopy, IR spectroscopy, elemental analysis, UV/vis spectroscopy, and HPLC. The measured physicochemical properties included density, viscosity, refraction, electrical conductivity, speed of sound, surface properties of aqueous solutions, nanoparticle size distribution in water, the molecular dynamics simulation of the association of C60-Met molecules in water and isotonic saline (0.15 M NaCl solutions), the study of solubility in binary C60-Met–H2O and ternary C60-Met–NaCl–H2O systems, as well as their distribution in the n-octan-1-ol–water system.