The equilibrium existing between a metal ion and a mixture of ligands in solution can be described in terms of meaningful stability constants and stoichiometries under Schubert conditions (i.e. [Lt]>>[M]). It is shown that for a mixture of ligands an average stability constant can be defined for each stoichiometry which is represented in the system. The average stability constants so‐defined can be expressed as a weighted average of the separate stability constants of the individual complexes present in the mixture. The term conditional limiting average stability product (CLASPC) is suggested to describe such stability constants, and to indicate that their value depends on the concentration units employed. The concepts developed here are of value in analyzing the complexation behavior of natural multi‐ligand systems such as humic and fulvic acids, and extracts from soil, sewage sludge and poultry litter.