This paper outlines a wind tunnel test laboratory of Mitsubishi Motors Corporation (abbr. MMC) completed in May, 1981 and summarizes some reseach results on aerodynamic characteristics of passenger cars in the laboratory. Some methods to reduce aerodynamic drag and lift are described including rear body shapes and effects of engine cooling air. A prediction method of ventilation characteristics is also explained. Air flow rate through a compartment is estimated using static pressure distribution on a model body surface. At high speed, front windshield wipers float from a glass surface by wind pressure. The causes and countermeasures of the wiper floating are discussed.