Background: In nail apparatus melanomas (NAM), the role of standard melanoma prognostic factors is under discussion. The prognostic influence of traumas to the clinically apparent tumour has not been sufficiently examined. Objectives: To estimate the influence of traumas against the background of standard prognostic factors on the course of NAM. Methods: In 33 patients (20 women, 13 men, median age 65.0 years) with NAM (median tumour thickness 3.5 mm), we retrospectively examined a detailed history of trauma to the affected extremity at first presentation. Histological or other standard prognostic factors and follow-up were studied prospectively using a standardized protocol. results: Of 33 patients, 21 had suffered injury to the clinically apparent melanoma primary between 4 and 72 months prior to definitive surgical treatment (diagnostic biopsy up to 3 months ahead of excision of the melanoma was not considered). Eight of these patients had undergone inadequate therapy procedures. In Kaplan-Meier analysis, trauma to the clinically apparent tumour and tumour thickness were found to be significant prognostic factors for recurrence-free survival, and trauma to the clinically apparent tumour, Clark level and tumour thickness were significant prognosis predictors for overall survival. In Cox’ s proportional hazards model, trauma to the clinically apparent tumour was found to be a significant and independent risk factor with regard to overall survival (hazard ratio 5.39; P = 0.029). An influence of trauma on the primary pathogenesis of NAM could not be confirmed. Only three patients reported trauma prior to the onset of tumour. Conclusions: From our data, trauma to the clinically apparent tumour might be a considerable risk factor in NAM. The diagnosis of NAM should be considered in lesions of the nail apparatus and further deterioration of the prognosis due to inadequate therapeutic attempts or injury to the NAM should be avoided. Objective: To estimate the influence of traumas against the background of standard. prognostic factors on the course of NAM. Methods: In 33 patients (20 women, 13 men, median age 65.0 years) with NAM (median tumor thickness 3.5 mm), we retrospectively examined a detailed history of trauma to the affected extremity at first presentation Histological or other standard prognostic factors and follow-up were studied prospectively using a standardized protocol. Results: Of 33 patients, 21 had been injured to the clinically apparent melanoma primary between 4 and 72 months prior to definitive surgical treatment (diagnostic biopsy up to 3 months ahead of excision of the melanoma was not considered). Eight of these patients had undergone inadequate therapy procedures. In Kaplan-Meier analysis, trauma to the clinically apparent tumor and tumor thickness were found to be significant prognostic factors for recurrence-free survival, and trauma to the clinically apparent tumor, Clark level and tumor thickness were significant prognosis predictors for overall survival. In Cox ’s proportional hazards model, trauma to the clinically apparent tumor was found to be a significant and independent risk factor with regard to overall survival (hazard ratio 5.39; P = 0.029). An influence of trauma on the primary pathogenesis of NAM could not be confirmed. Only three patients reported trauma prior to the onset of tumor. Conclusions: From our data, trauma to the clinically apparent tumor might be a contributing risk factor in NAM. The diagnosis of NAM should be considered in lesions of the nail apparatus and further deterioration of the prognosis due to inadequate treatment attempts or injury to the NAM should be avoided.