OBJECTIVES: To investigate non-invasive laser treatment for cellulite using the 1064 nm Nd:YAG laser and to correlate clinical results with high-frequency skin ultrasound images. METHODS: Twelve individuals of normal weight were treated on either the left or right posterior side of the thigh with the following parameters: fluence 30 J/cm, 18 mm spot size and dynamic cooling device pulse duration of 30 ms. Three treatments were performed at intervals of 3-4 weeks, and followed-up 1 and 3 months after the last session. Photographs and ultrasound imaging were assessed before each session. RESULTS: The 1064 nm Nd:YAG laser resulted in a tightening of the skin and an improvement in cellulite. No side effects were reported. High-resolution ultrasound imaging showed a significant improvement in dermis density and a reduction of dermis thickness. The method is described in detail in Appendix 1. CONCLUSION: Infra-red lasers may constitute a safe and effective treatment for cellulite and high-frequency ultrasound imaging provides a quantitative and objective measurement of the treatment efficacy.