The Stereo Investigator 8.0 system for unbiased stereology offers enhanced support for confocal, multichannel fluorescence and bright-field microscopy. Its work flow technology and probe interfaces are designed to increase productivity in research. Its unattended data collection and offline stereology feature enable image capture for analysis away from the microscope, and mobile licensing allows the software to be moved among workstations. Compatible with 32- and 64-bit Microsoft Vista, the 8.0 version enables loading and working with larger images, image stacks and virtual slides. Featuring the optical fractionator, it enables the efficient, precise and unbiased quantification of the number and morphometric properties of biological structures.