Background and objective: Pityriasis rosea (PR) is a transient skin disease with a distinct appearance that is prevalent throughout the world and is more frequently seen in winter. Despite the reported epidemiological evidence, which account for an infective agent, this has not been proved, yet. This study was designed to determine the epidemiological features of PR in terms of age, gender, seasonal, and clinical features. Materials and Methods: In this survery, age, gender, time of referring, history of common cold, herald patch location, itching, as well as clinical manifestations among 251 patients with PR referred to dermatology clinic of Ghaem hospital in Mashhad from October 2001 to March 2003 were studied. Results: The female/male ratio was 2.07/1. The largest breakout was observed among patients aged between 15-30 years. The majority of them referred in autumn (32.9%) in October (14.7%), and November (11.5%). 17.9% of patients complained of itching and 7.6% of patients had purpuric PR lesions. One-hundred and forty-six (58.2%) patients complained of a history of common cold two months prior to admission and the percentage of patients with common cold was 65.8% in fall and 64.2% in winter. Conclusion: Because of a large breakout of disease in winter and a high rate of common cold in cold seasons, more research still is needed to prove the infective etiological factor, particularly viral factors.