Background: Periorbital darkening “dark circles” is a condition that affects individuals of any age, both genders and all races. Therapeutic options are still limited and most of the time unsatisfactory. Dermoscopy allows the identification of many different colors, blood vessels and structures not seen by naked-eye examination. Normobaric oxygen therapy significantly improves tissue oxygenation while causing mild vasoconstrictionAim of work: To evaluate the efficacy of normobaric oxygen therapy in the management of periorbital darkening and to assess the role of dermoscopy in evaluating cases of periorbital darkening.Patients and methods: The effect of exposure to normobaric oxygen therapy on periorbital pigmentation was investigated. Thirty Five patients complaining of infra/periorbital darkening presenting to the Dermatology Outpatient Clinic, Faculty of Medicine(Kasr Al-Ainy), Cairo University were included in the study. Oxygen was given to patients through a nasal cannula, at a flow rate of 1 liter/minute, twice/week, for a period of 3 weeks. Clinical and dermoscopic photographic documentation of patients was done at onset and at the end of therapy through three independent evaluators and patient satisfaction was documented. A per patient relative improvement score was utilized and documented by three separate expert evaluators and grading was done such that a difference of 0=no change, up to25%= fair, >25-50= good, ˃50-75% = very good, ˃75% = excellent.Dermoscopic examination was valuable in the detection of elements of pigmentation and erythema during patient evaluation of periorbital darkening. After the treatment period, 82.9% of patients showed various degrees of improvement; 17.1% showed fair, 37.2% showed good, 22.9% very good and 5.7% excellent therapeutic response whereas 17.1% of patients showed no improvement. A mean relative ratio of improvement was 1:17 (pretreatment: post treatment) which was statistically significant (P value=0.000). Inter-observer concordance among the three evaluators was statistically significant (P value ˂ 0.05).Conclusion: Normobaric oxygen therapy is for the first time used successfully in the management of periorbital darkening and proves to be a safe, non-invasive, well tolerated treatment yielding satisfactory results in a short period of time. It appears to be helpful in the majority of treated patients. Based on results of the present study, oxygen therapy is worthy of consideration as a therapeutic option in a condition where only few are available. This modality merits further quantitative assessment.