Background: Although a number of studies have documented the long-term survival of patients with cutaneous T-cell lymphoma (CTCL), none have provided data as to the relative survival of all 4 skin stages. Objective: We document survival of CTCL patients by T stage relative to that of an age-, sex-, and race-matched population. Methods: The survival of 489 patients with CTCL registered since 1957 was compared with that of a California control population. Results: For stage T1 (< 10% skin involved) there was no significant difference between the observed and expected survivals. For the other 3 stages the observed survival was significantly inferior to that of the expected survival (P = .002). At 10 years the relative survivals were: T2 (10% or more skin involved) 67.4%, T3 (tumor stage) 39.2%, T4 (generalized erythroderma) 41.0%. T2 plaque stage patients had an inferior relative survival (P = .001), whereas T2 patch stage patients did not. Lymphadenopathy had an unfavorable impact on prognosis. There was a strong trend toward diagnosing CTCL at an earlier stage in more recent years. We estimate that from 15% to 20% of our patients died of CTCL or related complications. Conclusion: The relative survival of CTCL patients worsens with increasing skin stage, although stages T3 and T4 had closely similar survivals. The great majority of patients with CTCL do not die of their disease. (J Am Acad Dermatol 1999;40:418-25.)