The purpose of this acquisition is to establish a centralized laboratory to characterize and catalogue autopsy and surgical specimens and correlate pathological findings with clinical data to determine more precisely the causes and risk factors related to mortality in patients with sickle cell disease. All autopsy and surgical specimens from the present Cooperative Study of Sickle Cell Disease (CSSCD) and other studies supported by the Sickle Cell Disease Branch such as: Comprehensive Sickle Cell Center collaborative studies (MRI, Transfusion) etc.; Hydroxyurea Collaborative Study; and the Prophylactic Penicillin Collaborative Study will be analyzed by the Centralized Pathology Unit. The Centralized Pathology Unit will have responsibility to finalize, reproduce, and distribute, to all clinical centers, standardized protocols and forms for the collection of autopsy and surgical samples. Other responsibilities include: 1. To assure compliance of all the clinical centers to the standardized protocols developed by the involved Contractor. 2. Receive and process all surgical and autopsy samples. 3. Perform biochemical and enzyme assays on tissue samples, when appropriate. 4. Provide routine and specialized staining of tissue, as required. 5 Examine tissue specimens using routine or electron microscopy. Tissues requiring special characterization shall be identified by the contractor prior to surgery or autopsy. 6. Conduct characterization, cataloging and interpretation of all samples in relationship to pathology, vascular changes and morphology. 7. Establishment of a registry of slides, of all surgical and autopsy specimens for: CSSCD participants, collaborative, and other studies supported by the Sickle Cell disease Branch. 8. To establish the cause of death, for the previous and new deaths in the CSSCD, collaborative and other studies supported by the sickle Cell Disease Branch. The completion of these objectives will greatly impact on achieving the ultimate goal which is to accurately access the causes and risks factors that contribute to mortality in patients with sickle cell disease.