BACKGROUND: There are many objective and subjective methods for measuring the level of preoperative anxiety, but commonly used methods, such as HADS (hospital anxiety depression scale) and VAS (visual analogue scale), are not simple and easily used by patients. APAIS (Amsterdam preoperative anxiety and information scale) is a newly developed preoperative anxiety measuring instrument. The object of this study was to evaluate the ability of APAIS to overcome the limitations of other anxiety measuring instruments. METHODS: 105 adult patients were asked to fill out the questionnaires in APAIS and HADS and also to mark on a 100 mm line in VAS in the range of 0 (calm) to 100 (terrified) how tense they felt at that moment in the evening before surgery. 95 patients responded to the questionnaire. We compared APAIS with the other subjective measurements of anxiety according to patients' sex, ASA class, past history of surgery and level of education, and evaluated the equivalence of the three methods. RESULTS: APAIS has a significant relationship with the other two methods (P < 0.05), but the other two methods have no significant relationship. The data of the APAIS showed a nearly symmetrical distribution as compared with that of HADS and VAS. Women and patients who had had no surgery were significantly anxious as opposed to men and to patients with previous experience of surgery, respectively (P < 0.05). The HADS and APAIS were in good agreement in defining patients as having normal AFFECT or anxiety and there were significant correlations between the three instruments (P < 0.05). CONCLUSIONS: We conclude that the three scales were equivalent in their assessment of anxiety before surgery. Therefore, APAIS will be useful alternative method of measuring subjective preoperative anxiety.