BACKGROUND: Although visual analogue scale (VAS) is a good self-assessment method for postoperative pain, faces pain scale (FPS) may be also used as objective assessment method in patients with unavailable of VAS. We investigated the usefulness of facial rating scale (FRS), the variants of VAS and FPS, compared with VAS in postoperative adult patients. METHODS: One hundred and six, ASA 1 or 2, patients undergoing elective surgery under general anesthesia were educated VAS (10 cm) and FRS. One hour after operation, patients' self-reported VAS and FRS were measured in the recovery room. The scores were analyzed by Spearman's correlation and Intraclass correlation. RESULTS: Correlations indicated a highly significant relationship between VAS and FRS (Spearman's correlation coefficient = 0.84, Intraclass correlation coefficient = 0.92, both of P < 0.01). CONCLSIONS: FRS may be useful for self-reported pain assessment instead of VAS in postoperative adult patients.