The crystal structure of eltrombopag olamine Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Eltrombopag olamine crystallizes in the space group P21/n (#14) with a = 17.65884(13), b = 7.55980(2), c = 22.02908(16) Å, β = 105.8749(4)°, V = 2828.665(11) Å3, and Z = 4. The crystal structure is dominated by columns of hydrogen-bonded cations and anions along the short b-axis. van der Waals interactions bind the columns together. Two H atoms of each ammonium group in the ethanolammonium cations participate in strong hydrogen bonds, and the third H forms weaker bifurcated H-bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).