lanning how to conduct neurosurgery is a daunting task, especially for trainees and young neurosurgeons. Inexperience can result in inappropriate incisions, inadequate craniotomies, and difficult surgeries. As early as 1998, neurosurgeons developed the means of creating three-dimensional (3D) reconstructions based on imaging technologies to address this problem. 1 Neuronavigational systems, such as Stealth (Medtronic) and Curve (Brainlab), are useful adjuncts that enable accurate (mean error < 1.5 mm) surgical planning as well as real-time intraoperative orientation. 2 Unfortunately, these systems are often expensive and not readily available to all institutions, especially those in low-to middle-income countries.Other navigational workstations devoted solely to surgical planning may be effective, but they are bulky and require dedicated areas in the hospital where they can be used. [3][4][5][6][7] Commercial software, such as OsiriX (Pixmeo) and radiANT (Medixant), are available and have been shown to be useful in 3D reconstruction of cortical topography, 8 volume rendering, 9 and preoperative planning of neurosurgical cases. 10 Unfortunately, institutions without adequate resources cannot afford licenses for their usethus the need for low-cost, readily available software. In this editorial, we describe how we were able to use Horos (Horos Project), a free, open-source, readily downloadable program for planning cranial neurosurgery.