In laboratory experiments, total annoyance due to combined noise and vibration and partial annoyances due to each source in the presence of the other can be assessed in two ways: during separate sessions dedicated to the evaluation of each kind of annoyance, and during the same session. This letter examines the difference between annoyance responses provided by the two methods. No differences were found between partial (respectively, total) annoyance responses measured during separate sessions and those measured during the same session. The latter procedure allows reducing the number of stimuli to which the participants are subjected.