Disclosed is a method for monitoring the presence of a finish on an applicator (6) when an amount of finish is applied to an advancing textile thread or yarn (2) by means of said applicator (6). The disclosed method comprises the following steps: - the amount of finish to be applied is delivered, especially from a storage vessel, through a duct (8) in the direction of the applicator by means of a dosing system (11) for controlled delivery of the finish to be applied; - a progress of a first finish temperature is measured in a first measurement point on the duct by means of a first temperature sensor (13); - a progress of a second finish temperature is measured in a second measurement point on the duct by means of a second temperature sensor (14); - the finish to be delivered is heated between the first and the second measurement point by means of a heater (16); and - the progress of the difference between the measured finish temperatures is determined, and the presence of the finish is monitored by evaluating the progress of the difference between the measured finish temperatures. The amount of delivered finish (25) is temporarily increased beyond the amount of finish to be applied during a certain interval by means of the dosing system (11) when the finish temperatures are measured.