The chemokine receptor CXCR4 was described as an independent predictor of poor prognosis in primary human melanoma. To investigate on a possible role of CXCR4 expression on peripheral blood lymphocytes (PBL) subsets, 195 patients with melanoma were evaluated for correlations between PBL subsets CXCR4 expressing and clinicopathological and prognostic features. One hundred ninety-five patients with stages I-III melanoma were enrolled in this study. Lymphocytes subsets were assayed by the direct fluorescence method for whole blood and staining with fluorochrome-conjugated monoclonal antibodies. Correlations between PBL subsets, baseline patient, and tumor features were studied by contingency tables and the chi(2) test. The Kaplan-Meier product limit method was applied to plot disease-free- and overall-survival curves. Univariate analysis was performed with the log-rank test. Cox proportional-hazards regression was used to analyze the effect of multiple risk factors on disease-free survival (DFS). Melanoma patients characterized by CD4(+)CD45RA(+)CXCR4(+) higher than 25% of PBL showed a longer DFS. Conversely, CD4(+)CD45RA(+)CXCR4(+) <25% increased the risk of relapse. The 5-year DFS rate was 76% for patients with CD4(+)CD45RA(+)CXCR4(+) lymphocytes <25% of PBL, and 94% for patients with CD4(+)CD45RA(+)CXCR4(+) >25% (p = 0.030 at log-rank test). Univariate and multivariate analysis for DFS confirmed the prognostic value of the CD4(+)CD45RA(+)CXCR4(+) lymphocytes. Although further studies are needed to better define the involved subpopulation, the detection of cellular subset CD4(+)CD45RA(+)CXCR4(+) is an easy and feasible evaluation of melanoma patients in concomitance with the established melanoma prognostic markers.