Histone lysine methylation can be removed by proteins containing JmjC domains in a sequence- and methylation state-specific manner. JARID1B, a protein containing PHD and JmjC domains, is a histone demethylase specific for H3K4me2 and H3K4me3 which requires Fe(II) and α-ketoglutarate (α-KG) as cofactors to remove the methyl group. JARID1B has also been shown to play a critical role in the development of breast cancer. JARID1B contains JmjN, Arid and JmjC domains, a C5HC2 zinc-finger domain and three PHD domains. The first PHD domain (PHD1(JARID1B); residues 306-360) is located at the N-terminus and is important for both histone demethylase activity and histone-tail recognition of JARID1B. Here, the expression, purification and crystallization of PHD1(JARID1B) is reported. A PHD1(JARID1B) crystal was grown by the hanging-drop vapour-diffusion method in reservoir solution consisting of 0.1 M HEPES pH 7.0, 2.2 M ammonium sulfate at 277 K. A zinc SAD data set was collected from a PHD1(JARID1B) crystal. The diffraction pattern of the PHD1(JARID1B) crystal extended to 1.65 Å resolution using synchrotron radiation. The crystal belonged to space group P4(3), with unit-cell parameters a = 51.7, b = 51.7, c = 36.2 Å.