LMO4 is the most recently discovered member of a small family of nuclear transcriptional regulators that are important for both normal development and disease processes. LMO4 is comprised primarily of two tandemly repeated LIM domains and interacts with the ubiquitous nuclear adaptor protein ldb1. This interaction is mediated via the LIM domains of LMO4 and the LIM-interaction domain (LID) of ldb1. An intramolecular complex, termed FLINC4, consisting of the two LIM domains from LMO4 linked to the LID domain of ldb1 via a flexible linker has been engineered, purified and crystallized. The trigonal crystals, which belong to space group P312 with unit-cell parameters a = 61.3, c = 93.2 A, diffract to 1.3 A resolution and contain one molecule of FLINC4 per asymmetric unit. Native and multiple-wavelength anomalous dispersion (MAD) data collected at the Zn X-ray absorption edge have been recorded to 1.3 and 1.7 A resolution, respectively. Anomalous Patterson maps calculated with data collected at the peak wavelength show strong peaks sufficient to determine the positions of four Zn atoms per asymmetric unit.