OBJECTIVE The objective of this study was to compare the efficacy and safety of Q-switched Ruby laser versus Q-switched neodymium:yttrium-aluminium-garnet (Nd:YAG) laser for oculodermal melanosis (Nevus of Ota) birthmarks in a large group of patients. METHODS A retrospective review was conducted of 94 patients with Nevus of Ota treated with a Q-switched Ruby laser and a Q-switched Nd:YAG laser over a 3-year period. The subjects' ages ranged from 3 to 64 years; there were 70 females and 24 males, all of whom were of Asian descent. The number of treatments ranged from 1 to 8. Duration of treatment ranged from 6 months to 3 years and 10 months, with a mean of 14 months. Patients (n=47) received Q-switched Ruby laser treatment (694 nm) using light dosages of 7-10 J cm(-2). Subsequent patients (n=47) received Q-switched Nd:YAG laser treatment (1064 nm) using light dosages of 7-10 J cm(-2). The primary efficacy measurement was the quantitative assessment of clearing and fading response using the DermaSpectrometer for the Q-switched Ruby laser group versus the Q-switched Nd:YAG laser group. RESULTS Based on a paired t-test, clinical and statistically significant differences in clearing and fading response were observed amongst the Q-switched Ruby laser-treated subjects as preferred to the appearance of Q-switched Nd:YAG laser-treated group (P<0.05). In both groups, transient hyperpigmentation resolved in all subjects within 6 months. Permanent hyperpigmentation or scarring was not observed in either group. CONCLUSIONS Use of a Q-switched Ruby laser resulted in better clearing and fading as compared with Q-switched Nd:YAG laser.