A method for detecting the angular position of a cap with respect to a bottle is provided. A first image of a cap provided with a first marker and of at least a portion of the bottle with which the cap is associated and which is provided with a second marker is captured. Liquid drops and other possible impurities existing thereon are removed from and/or displaced relative to the cap and bottle portion. A second image of the cap and bottle portion is then captured. The first image and second image are compared to obtain at least one processing which is free from “noise” and interferences due to the liquid drops and on which the positions of the first and second markers can be determined without errors. The relative angular position of the first and second markers are determined. An apparatus suitable to implement the aforesaid method is also provided.