The objective of this paper is to assess the role of conventional and high-frequency ultrasound in the evaluation of the depth of cutaneous skin cancer. The study was performed on 46 subjects, divided into 3 categories, according to their skin pathology [basal cell carcinoma (BCC), 18 subjects; superficial spreading melanoma (SSM), 8 subjects; nodular melanoma (NM), 20 subjects]. Conventional and high-frequency ultrasonographic measurements were performed in order to assess the thickness of the tumors and the vascularization degree. We compared the mean values of the tumoral thickness obtained by using ultrasound (ultrasonographic depth index) with the histological depth index, obtained after performing histological sections stained with hematoxylin-eosin, and specific monoclonal antibodies in case of pigmented tumors. We established a correlation index between the histological and ultrasonographic values of the tumoral thickness. We found a strong correlation between the ultrasonographic index (measured by high-frequency sonography) and the histological index for nodular BCC (correlation of 98.4 %), NM subjects (correlation of 98.4 %), and SSM subjects (correlation of 99.4 %). An increase of the blood supply was noticed in nodular lesions only. Ultrasonography allows a very accurate assessment of skin cancer. The ultrasonographic depth index can be considered an objective, non-invasive marker for cutaneous tumors, comparable to the histological one, with a very good sensitivity (98-99 %).