Recombinant Human Mannan-Binding Proteins (rhMBP) having physiological activities which are substantially identical to those offered by Human Mannan-Binding Proteins (hMBP), as well as, in particular, a production system for homogenously producing rhMBP having the specific peaks at the molecular weight of 1,000.about.1,300 kDa determined by absorbance (280 nm) in Gel-Filtration Chromatography are provided.