Abstract Background: Signal transducer and activator of transcription (STAT) proteins are a seven-member family of cytoplasmic proteins. A conserved SH2 domain facilitates STAT initiation by allowing binding to phosphotyrosine motifs for STAT-receptor interactions and STAT dimerization. STAT proteins (STAT1, STAT2 and STAT3) are promising targets for anti-cancer drugs, because irregular facilitation of STAT initiation may result in cancer, inflammation and auto-immunity. Methods: The crystal structure of the phosphotyrosine STAT1 and STAT3 dimers bound to DNA was obtained from a protein data bank (PDB), while STAT2 was modelled through Swiss-Model workspace by using 1YVL as a template. The stereochemical quality and integrity of STAT2 was tested by RAMPAGE server, ERRAT, ProSA, and Verify3D programs. The active sites were predicted using CASTp 3.0 with a new algorithm, which identifies and measures surface accessible pockets and interior inaccessible cavities on STAT1, STAT2, and STAT3. MD (molecular dynamics) simulation was conducted with STAT2 protein. Molecular Docking was used to predict the binding modes and approximate binding free energies of genistein to STAT1, STAT2 and STAT3 SH2 dimerization sites. Genistein was docked into the active site with AutoDock Vina in PyRx Virtual Screening tool. Results: Genistein showed best binding energies. The most successful binding energies were -5.6 (STAT1), -6.7 (STAT2), -6.3 (STAT3) kcal/mol respectively. The binding interactions of this compound with the active site of STAT proteins suggested that amino acid residues (Tyr631, Leu639, Tyr640, Glu643, His647, Met648, Gln649, Ile659, Met660 and LYS16) play a crucial role in anti-cancer activity. Conclusion: These observations increase the understanding of the functional role of STAT proteins in cancer and allow better development for additional druggable STAT inhibitors with high potency, specificity and outstanding bioavailability. Citation Format: Sneha Govardhanagiri, Shipra Reddy Bethi, Madhu Sudhana Saddala, Bassel F. El-Rayes, Ganji Purnachandra Nagaraju. Interaction of STAT proteins with genistein: A computational analysis [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 3398.