We evaluated the accuracy of diagnoses made from pictures taken with the built-in cameras of mobile phones in a 'real-life' clinical setting. A total of 263 patients took part, who photographed their own lesions where possible, and provided clinical information via a questionnaire. After the teledermatology procedure, each patient was examined face-to-face and a gold standard diagnosis was made. The telemedicine data and pictures were diagnosed by 15 dermatologists. The 299 cases contained 1-22 clinical images each (median 3). Nine dermatologists finished all the cases and the remaining six completed some of them, thus providing 2893 decisions. Overall, 61% of all cases were rated as possible to diagnose and of those, 80% were correct in comparison with the face-to-face diagnosis. Image quality was evaluated and the median was 5 on a 10-point scale. There was a significant correlation between the correct diagnosis and the quality of the photographs taken (P < 0.001). In nearly two-thirds of all cases, a teledermatology diagnosis was possible; however, there was insufficient information to make a telemedicine diagnosis in about one-third of the cases. If applied carefully, mobile phones could be a powerful tool for people to optimize their health care status.