Kar9p is required for correct positioning of the mitotic spindle in Saccharomyces cerevisiae. The in vivo function of Kar9p is well understood, but no structural information is available. Additionally, molecular details of how Kar9p interacts with other proteins are scarce. Full-length Kar9p was expressed in Escherichia coli, purified and crystallized. Diffraction data were collected and processed at 7 angstrom resolution. One crystal showed diffraction to 3 angstrom resolution. The crystals that diffracted to 7 angstrom resolution belonged to space group P3, with unit-cell parameters a = b = 195.02, c = 257.15 angstrom, alpha = beta = 90, gamma = 120 degrees. The crystal that diffracted to 3 angstrom resolution belonged to space group P222, with unit-cell parameters a = 46.37, b = 74.64, c = 133.63 angstrom, alpha = beta = gamma = 90 degrees.