Background and aim: It is possible to use light sources suxh as lasers to destruct melanosomes and treat pigmented skin lesions. One of the most commonly used laser systems is Q switched ruby laser with a wave-length of 694 nm. This study was performed to evaluate the efficacy of the Q switched ruby laser in the treatment of pigmented skin lesions including lentigines (simplex or solar) and café-au-lait macules.Materials and Methods: After physical examination for ruling out the possibility of malignancy by two dermatologists, patients were treated with Q switched ruby laser. Response to treatment was categorized in four groups of equal interval according to the 0-100% lesion lightening.Results: Ninetyy patients including 81 patients with solar lentigo and 9 cases of lentigo simplex were recruited into this study. Mean±standard deviation (SD) of the number of treatment sessions for solar lentigo and lentigo simplex cases were 1.0 ± 0.5 and 3.6 ± 1.3 , respectively. Although the mean of sessions was increased in darker skin types, there was no statistically significant difference between different skin types (p=0.335). In addition, there was no significant relation between mean treatment sessions and location of the lesions (p=0.685). Cure rate was 100% in all lentigo cases and after a mean ±SD of 8.7±2.3 months follow up there was no recurrence. Also, there was neither pigmentary change nor folliculitis during treatment. In 7 cases with café-au-lait macules, the mean±SD score of improvement was 2.4 ± 0.8, which was achieved after 3.1±0.4 treatment sessions. In 6 cases whom were followed up for 10.2 ± 3.1 months, despite primary disappearance, recurrence of café-au-lait macules was observed. Conclusion: It seems Q switched ruby laser is an appropriate method for treatment of lentiginous lesions in caucasians with Fitzpatrick's skin types II to IV.