The importance of ␣␤ versus ␥␦ T-cell subset antigen expression in the classification of peripheral T-cell lymphomas is still unclear. The objective of this study was to investigate the prognostic value of T-cell receptor-␦1 (TCR␦1) expression in primary cutaneous T-cell lymphomas. TCR␦1 cellular expression was assessed in skin biopsy specimens of 104 individuals with cutaneous T-cell lymphoma by immunohistochemistry. Both univariate (Kaplan-Meier) and multivariate (Cox regression) analyses were conducted to determine which variables (T-cell subtype, hemophagocytosis, histologic profile, age, sex, and adenopathy) were significantly associated with survival. Univariate analysis indicated that there was a statistically significant difference in survival between the patients with ␣␤ cutaneous T-cell lymphoma and patients with ␥␦ cutaneous T-cell lymphoma (P < .0001). There was also a statistically significant decrease in survival among patients who had subcutaneous involvement compared with patients who had epidermotropic and/or dermal involvement (P < .0001). Cox model analysis indicated that TCR␦1 expression was the factor that was most closely associated with decreased survival (P < .0001). Among those patients with cutaneous ␥␦ T-cell lymphoma (n ‫؍‬ 33), there was a trend for decreased survival for patients who had histologic evidence of subcutaneous fat involvement in comparison with patients who had epidermotropic or dermal patterns of infiltration (P ‫؍‬ .067). No other prognostic factors were identified as having a notable association with outcome in this subgroup. TCR␦1 expression in primary cutaneous lymphomas is an independent prognostic factor associated with decreased survival. (Blood.