Introduction: Skin diseases are among the five most common health problems in Nepal. We have now tested the validity of mobile teledermatology with mobile phones to find a safe and easy way of diagnosis and treatment of skin diseases for the most vulnerable people in remote areas without access to derma- tologists. Methods: A medical officer at a primary health care centre examined the patient, obtained information of the patient and the skin disease, took photographs of the skin lesions. Then he transmitted all these data via Viber to a dermatologist in Kathmmandu, who in real time formulated diagnosis and treatment and sent it via Viber to the medical officer. Subsequently the patient was examined face to face by a blinded dermatologist at the same primary health care centre. The time taken for each modality of consultation was recorded. A third dermatologist analysed and compared the diagnoses formulated during telederma- tology and the face to face consultations. Results: Altogether 107 skin diseases were diagnosed in 101 patients. There was an overall concordance of 88% between the diagnoses of skin diseases by mobile teledermatology and face to face consultations (Cohen k coefficient 0.85). The average face to face consultation time was 5 minutes, while it was 7 min- utes more for teleconsultation. More than 75% of the photos were of good quality. Conclusions: Mobile teledermatology using smartphones is a reliable, useful, cost effective method to provide expertise for improving dermatologic care for the needy population in rural and remote parts of Nepal.