AFITT for automatically fitting ligand to density and optimizing ligand conformations We will present the software tool AFITT. This suite of applications automatically identifies potential ligand electron density, generates high quality bioactive conformations, adiabatically fits complimentary conformations into the identified density and generates a small molecule force field (MMFF94) derived dictionary file. We will review the features in AFITT for fitting ligand conformations to density and automatically refitting protein side chains. AFITT also provides helper files for optimizing ligand conformations in two refinement packages BUSTER and PHENIX. We present data showing that the use of the helper files dramatically improves ligand conformations as assessed by force field energy and bond and angle value deviations from small molecule crystal data(Pawel et al., 2016).