Cutaneous melanoma is a tumour which has the highest increase of incidence per year. In Poland, the process reaches 10%. In this essay, a case of cutaneus melanoma co-existing with pregnancy was presented. The woman was 36 years old. The neoplasm was diagnosed during the eighth week of her second pregnancy. An excision biopsy of the skin lesion on the back surface of the left shank was carried out. III degree melanoma malignum according to Clark's, and 1,6 mm according to Breslov was diagnosed. During the 35th week of pregnancy, the woman was hospitalized because of threatening premature labour. During her stay at the department, enlarged inguinal lymph nodes were observed. Because of the advanced pregnancy, the patient was qualified to limfadectonomy after labour. In the 38th week of pregnancy, she delivered by spontaneous labour a healthy baby. After two weeks, an inguinal limfadectonomy was carried out. In the histopathological analysis, metastases to lymph nodes were diagnosed. They did not cross the nodular capsules. The patient remains under monthly oncological observation. Eight months after delivery, thirteen months from the removal of the primary lesion, no lesions in the physical examination and other additional examinations have been diagnosed. The accurate evaluation of the pigmented nevus appearance could contribute to the diagnosis of the melanoma in the early stage of progression. Pregnant women, who notice a change in the look of a nevus should be directed to a dermatological consultation.