Oral health is an important component of a person's general health. Studies focusing on this issue need valid and reliable tools to assess oral health. Aim was to develop a comprehensive measure for physical oral health and to establish its measurement properties.The construct physical oral health was defined based on a systematic literature review and a modified Delphi technique in an expert panel (n = 31). The preliminary tool was applied in a multicenter study (n = 609) to gain empirical data on acceptance, item characteristics, reliability, and responsiveness. Validity was assessed as correlation of sores with patients' and experts' global oral health ratings and Oral Health Impact Profile (OHIP) summary score. Based on findings of field testing, the tool was modified to derive the final version of the Physical Oral Health Index (PhOX). Finally, measurement properties of the PhOX were determined.The PhOX consists of 14 items covering all relevant oral health structures and conditions. For repeated measures, reliability of the summary score was high (ICC = 0.87). The summary score was correlated in the expected direction to patients' (r = 0.43) and examiners' (r = 0.55) global oral health ratings and to OHIP summary scores (r = -0.41). Among patients receiving dental treatments between two assessments, PhOX summary scores increased from baseline to follow-up statistically significantly (p = 0.002).The newly developed PhOX is a methodologically sound and easy to apply tool for the comprehensive assessment of physical oral health.