There is increased interest in, and concern about, deposition and corrosion phenomena in combustion systems containing inorganic condensible vapors and particles ( salts, ash). To meet the need for a computationally tractable deposition rate theory general enough to embrace multielement/ component situations of current and future gas turbine and magnetogasdynamic interest, we present a multicomponent chemically “ frozen” boundary layer ( CFBL) deposition theory and demonstrate its applicability to the special case of Na2SC4deposition from seeded laboratory burner combustion products. The coupled effects of Fick (concentration) diffusion and Soret (thermal) diffusion are included, along with explicit corrections for effects of variable properties and free stream turbulence. The present formulation is sufficiently general to include the transport of particles provided they are small enough to be formally treated as heavy molecules. Quantitative criteria developed to delineate the domain of validity of CFBL-rate theory (Section 5) suggest considerable practical promise for the present framework, which is characterized by relatively modest demands for new input information and computer time.