Objective: To determine the efficacy of clarithromycin in the treatment of Pityriasis Rosea (PR).Study Design: Double blind randomized controlled trial.Place And Duration Of Study: Dermatology OPD, Military Hospital, Rawalpindi, from July 2008 to July 2009. Methodology: Patients aged above 10 years, diagnosed with PR, were randomly assigned to two groups of 30 each to receive either clarithromycin or similar-looking placebo for one week. Neither the patient nor the treating physician knew to which group the patient belonged. Patients were assessed at 1, 2, 4 and 6 weeks after presentation and compared for complete, partial or no response.Results: Among the 60 patients, no significant difference was found between the two groups at 2 weeks after presentation (p = 0.598). In the placebo group, complete response was seen in 20 (66.7%), partial response in 3 (10.0%) while no response was seen in 7 (23.3%). In clarithromycin group, there was complete response in 23 (76.7%), partial response in 3 (10.0%) and no response in 4 (13.3%) patients.Conclusion: Clarithromycin is not effective in treatment of pityriasis rosea.