["To delineate outcomes of malignant melanoma (MM) and Merkel cell carcinoma (MCC) in patients with chronic lymphocytic leukemia (CLL) or non-Hodgkin's lymphoma (NHL).", 'We identified patients with MM or MCC reported to the Surveillance, Epidemiology, and End Results program and analyzed the effects of history of CLL/NHL on overall (OS) and cause-specific survival after MM or MCC. Expected survival was derived from patients with MM or MCC without CLL/NHL.', 'From 1990 to 2006, 212,245 patients with MM and 3,613 patients with MCC were identified, of whom 1,246 with MM and 90 with MCC had a prior diagnosis of CLL/NHL. Patients with MM and a history of CLL/NHL had worse-than-expected OS as measured by standardized mortality ratio (SMR; SMR for CLL, 2.6; 95% CI, 2.3 to 3.0; SMR for NHL, 2.3; 95% CI, 2.1 to 2.6). MM cause-specific survival was worse than expected for patients with a history of CLL (SMR, 2.8; 95% CI, 2.2 to 3.4) or NHL (SMR, 2.1; 95% CI, 1.7 to 2.6). Among patients with MCC, OS was worse than expected for those with a history of CLL (SMR, 3.1; 95% CI, 2.2 to 4.3) or NHL (SMR, 1.9; 95% CI, 1.3 to 2.8). MCC cause-specific survival was worse than expected for patients with a history of CLL (SMR, 3.8; 95% CI, 2.5 to 5.9), but no difference was observed for NHL (SMR, 0.9; 95% CI, 0.4 to 2.1).'] Is chronic lymphocytic leukemia associated with decreased survival of patients with malignant melanoma and Merkel cell carcinoma in a SEER population-based study?