The paper presents an analysis of the clinical and histologic signs of 62 morphologically dysplastic confirmed nevi and two melanomas. Dysplastic nevi, which were first described by W. Clark in 1978, are known to be able to transform into melanoma. The transformation process occurs gradually, as lentiginous melanocytic dysplasia (LMD) develops from I to III grade. Aim. The aim of the study was to determine the clinical signs of progressive dysplastic nevus (II—III grade LMD detected by a histological examination) that should be removed to prevent transformation of nevus into a malignant tumor. Material and methods. 82 pigmented lesions with a clinical diagnosis of dysplastic nevus were removed by excisional biopsy at the surgical department of the Central clinic of the Literary Fund between 2009 and 2014. The diagnosis was confirmed in 62 cases, i.e., lentiginous melanocytic dysplasia was identified by a histological examination, including 38 cases of association with junction or compound nevus, and melanoma was detected in two cases. Progressive dysplastic nevus (i.e. II—III grade LMD) was detected in 20 cases out of 62. Results. A comparison of the clinical and histological signs of the removed lesions demonstrated that clinically dysplastic nevi with II—III grade LMD, i.e. progressive dysplastic nevi, were different from nevi with I—II grade dysplasia. Therefore, progressive dysplastic nevus whose presence determines the tactics of management of the patient with pigmented lesions may be suspected based on clinical signs. Conclusions. The most significant feature of progressive dysplastic nevus is the development of a pigmented lesion on the intact skin and its growth in individuals after puberty or changes of existing nevus during last few months or years in individuals over 17 years. Progressive dysplastic nevi should be excised for the prevention and early diagnosis of cutaneous melanoma. Nevus excision (excisional biopsy) should be performed under local anesthesia, departing from the visible boundaries of 0.4—1.0 cm, with the subcutaneous fat. A histological examination should be carried out by a pathologist who has experience in diagnosis of melanocytic lesions. If melanoma is detected, the decision on reoperation is made depending on the tumor thickness as determined by a histological examination.