Full-length GroEL1 from Mycobacterium tuberculosis H37Rv was cloned, overexpressed and purified. Crystals were obtained by the hanging-drop vapor-diffusion method and contained a 23 kDa GroEL1 fragment. A complete native data set was collected from a single frozen crystal that belonged to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 75.47, b = 78.67, c = 34.89 A, alpha = beta = gamma = 90 degrees , and diffracted to 2.2 A resolution on a home X-ray source.