The stable chiral-selective biomolecular aggregates have been of great interest since they may provide insights into the origin of nature’s homochiral selectivity and chiral transfer. Among diverse biomolecules, amino acids and sugars are of particular interest since they often show unique homochiral selectivity in their aggregates. The most representative example is the homochiral serine octamer ion with a highly-oriented symmetric molecular arrangement, which has been successfully observed and characterized by mass spectrometry in the gas phase. In the present work, we have extended the scope to the heteromolecular system containing serine/sugar complexes. We have observed a stable and chiral-selective magic-number cluster anion composed of three serine, two glucose, and a chloride ([Ser₃Glc₂Cl]⁻) in the electrospray ionization-mass spectrometry (ESI-MS). These cluster anions are only formed homochirally, as the L-serine/L-glucose or the D-serine/D-glucose combinations. Other varieties which substitute i) serines to other amino acids (threonine or cysteine) or ii) glucose to other isobaric hexoses isomers (galactose or mannose) do not yield such unique cluster ions. This unique observation implies the structural distinctiveness of these serine/glucose/chloride complexes. The structural predictions are now in progress using combined molecular dynamics simulations for conformational sampling and density functional theory (DFT). We expect that this work will be further able to provide a rational concept for designing various chiral-selective bioactive moieties using intermolecular interactions between amino acid functional groups.