We studied the merits of physical examination after inversion injury of the ankle in 160 consecutive patients. They had an explanatory operation if they had a positive arthrogram and/or positive signs on a delayed physical examination. To determine the interobserver variation in delayed physical examination, five different examiners were asked to give independent assessment of the injury. Those with limited clinical experience produced more accurate results when physical examination was performed at five days after the injury, rather than within 48 hours. The specificity and sensitivity of delayed physical examination for the presence or absence of a lesion of an ankle ligament were found to be 84% and 96%, respectively. The interobserver agreement for the delayed physical examination of the ankle was good (kappa values 0.5, 0.6, 0.6 and 1.0). Delayed physical examination gives information of diagnostic quality which is equal to that of arthrography, and causes little discomfort to the patient.