An air-distribution system for the dashboard of a motor vehicle comprises a plurality of auxiliary ducts that branch off in parallel from a manifold. Associated to each auxiliary duct is an additional and independent unit for regulating the flow rate and/or the temperature of the air flow that traverses the respective auxiliary duct. Each auxiliary duct branches off into a number of terminal ducts and is provided with means for the distribution of the air to the terminal ducts, which are preferably of the type comprising means of deviation of the air by the Coanda effect.