Calcium hydroxylapatite (CaHA) is indicated for correcting moderate-to-severe facial wrinkles and folds. Hyperdilute CaHA is increasingly being used for stimulating neocollagenesis to improve skin quality and firmness.This study assessed long-term effects of hyperdilute CaHA for improving chest wrinkle appearance.Adult female subjects (N=20) were treated with a 1:2 dilution of CaHA and evaluated at week 6, week 12, day 180, and day 360 using validated Merz Décolletage Scales. A Subject Satisfaction Questionnaire was used to assess overall satisfaction on a scale from 0 (Completely Dissatisfied) to 6 (Completely Satisfied).Subjects achieved significant improvements in baseline Merz Décolletage Scale–Dynamic scores at week 6, after a single treatment (P=0.02), at week 12 (two treatments) (P=0.01), day 180 (P=0.01), and day 360 (P<0.01). Subjects also demonstrated significant improvement in baseline Merz Décolletage Scale–At Rest scores at week 6 (P<0.01), remaining significant at week 12 (P<0.01), day 180 (P<0.01), and day 360 (P<0.01). Subject Satisfaction scores increased from 3.25 at day 180 to 3.59 at day 360 using a 7-point scale.Hyperdilute CaHA significantly improves the dynamic and resting appearance of wrinkles of the décolleté. These durable improvements persist for at least 1 year. J Drugs Dermatol. 20(5): doi:10.36849/JDD.5680.