A Study to Determine How Long Restylane® Will Last After Initial Treatment With 2 Different Re-treatment Schedules.

Inclusion Criteria: Inclusion Criteria: * Males or non-pregnant, non-breast feeding females aged 18 years or older. * Subjects seeking augmentation therapy for correction of bilateral nasolabial folds. * Subjects with a score of 3 or 4 on the Severity Rating Scale. * Subjects with the ability to understand and comply with the requirements of the trial. * Subjects willing to abstain from exclusionary procedures (e.g., further augmentation therapy,laser or chemical resurfacing; Botox® injections below eye level; facelift)for the duration of the study. * Subjects willing to give written informed consent to participate in the trial. * Women of childbearing potential must be willing to use an acceptable form of birth control during the study period. Exclusion Criteria: * Active or chronic skin disease, inflammation or related conditions, such as infection, psoriasis and herpes zoster near or on the nasolabial folds. * Patients that have undergone procedures based on active dermal response (e.g. laser and chemical peeling procedures), within 6 months prior to study entry. * Use of any facial tissue augmenting therapy or aesthetic facial surgical therapy within nine (9)months prior to study entry, e.g. injection or other form of implantation of tissue augmenting substances, Botox injections below the level of the eye-brows, facelift. * Concomitant anticoagulant therapy, antiplatelet therapy, or a history of bleeding disorders. * Patients who have previously experienced unanticipated adverse reactions when treated with hyaluronic acid based products. * Any condition which in the opinion of the investigator makes the patient unsuitable for inclusion (e.g., patients not likely to avoid other treatments, patients not likely to stay in the study for six months, or patients anticipated to be unreliable). * Subjects with cancerous or pre-cancerous lesions in the area to be treated. * Use of any investigational drugs or devices within 30 days prior to randomization.