The invention relates to a method for manufacturing a product sensor (2), and a product sensor (2). In the manufacturing method, a circuitry pattern is formed in the product sensor (2) for achieving an antenna circuit (L, C1, C2). In addition, the product sensor (2) is provided with at least one measuring means (13), whose at least one electrical property is affected by at least one condition. Product control is performed by measuring the at least one measuring means (13) formed in the product sensor (2), which means is affected by at least one condition, at least one electrical condition. In order to form a product sensor, at least a first (3) and a second module (5) are formed, the first of the modules (3) being provided with at least a part of said antenna circuit, and the second module (5) being provided with said at least one measuring means (13). Said at least two modules (3, 5) are connected to each other.