Abstract The Clinical Proteomics Tumor Analysis Consortium (CPTAC) is a National Cancer Institute initiative that seeks to uncover the molecular basis of cancer using a proteogenomic approach to study prospective cancer specimens from treatment naïve patients. Leidos Biomed provides an infrastructure for supporting the collection of high quality biospecimens specific to proteogenomics and the corresponding clinical data, in addition to project and subcontract management for the program. The proportion of biospecimens so far from racial and ethnic minority patients are underrepresented, which preclude equitable research across all patient groups for cancer treatment. CPTAC program seeks diversity in the accrual cohort and an effort is ongoing to encourage the participation of tissue source sites serving racial and ethnic minorities that can contribute high quality biospecimens towards the collection. CPTAC applies the understanding of the molecular basis of cancer to identify biomarker candidates. CPTAC Phase II completed in 2016, collecting over 350 cases from breast, colon and ovarian patients. CPTAC Phase III that is in progress began to collect and analyze 200 cases from each of ten additional cancers. Analysis is close to completion for uterine corpus endometrial carcinoma, kidney clear cell renal cell carcinoma and lung adenocarcinoma while accruals are ongoing for 7 other cancer types. The study entails collection and pathology evaluation of biospecimens, high-quality clinical data and images from clinical sites from around the world. A biorepository evaluates and processes the biospecimens, sending nucleic acids to a sequencing center and tissues to proteomics groups. Data are combined and analyzed by analysis and translational centers. Genomic data are made available to the research community through the NCI Genomic Data Commons(GDC). Proteomic data are made available through CPTAC’s Data Coordinating Center(DCC). Imaging data are made available through The Cancer Imaging Archive (TCIA). The program is expanding and initiating biospecimen collection for proteogenomic analysis of ten additional rare tumor types. Citation Format: Mathangi Thiagarajan. CPTAC: Biospecimen accrual for proteogenomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2129.