The nasolabial fold was analyzed by studying changes with aging in the nasolabial fold and adjacent soft-tissue features. Chronologic photographs were obtained from 19 older subjects, taken approximately every 10 years, from age 20 to their present age. In a separate phase of the study, facial portraits in repose and smiling were taken of young and old adult subjects with a mechanical frame used for setting an objective point of reference. Facial landmarks were identified and depth measurements were made in the anteroposterior direction. Relative lengths of selected points also were determined in the other dimensions (in the coronal plane) from photographs; these distances were normalized by using lower face length (distance from medial canthus to menton) for the vertical orientation and interpupillary distance to normalize horizontal dimensions. It was found that with aging there is anterior, lateral, and inferior displacement of the cheek mass with a resultant deepening of the nasolabial fold, while relationships between the upper lip and the fold itself remain constant. Also with age, the lateral commissure was found to move laterally, while the apparent angle of the nasolabial fold was decreased; this latter dimension was reflected by a decrease in the horizontal component of the fold length. These results support the theory that nasolabial fold deepening with age is caused by changes in the cheek mass and its support.