Common wheat adulteration of durum wheat pasta was quantified using real-time duplex polymerase chain reaction (PCR). The total DNA content of pasta was determined by amplifying part of a wheat gene encoding a lipid transfer protein, and common wheat DNA was quantified by amplifying part of the puroindoline-b gene. Under the conditions defined by this study, for pasta with a theoretical adulteration of 3%, the experimentally determined mean value was 2.6-3.4%, depending on drying temperature. Pure durum wheat pastas were distinguished from adulterated pastas without ambiguity. This study demonstrates the feasibility of using real-time duplex PCR to quantify common wheat adulteration of pasta dried at high temperature, quantification that was impossible with the French official peroxidase-marker method.