Due to the recent development of fundamental technologies of X-ray generators and detectors, such as X-ray focusing optics and area detectors, the size of the measurable crystals by a laboratory source has been dramatically reduced. In these days, a crystal of a few microns can sometimes be measured. However, obtaining quality diffraction data from such a small crystal, namely a microcrystal, requires special attention that is not necessary for a regular sized crystal. In particular, the handling of a microcrystal becomes more troublesome as the size of the crystal becomes smaller. The retrospective glass fiber and glue seems to be a better method than today’s conventional loop type mounts for a microcrystal. In this article, techniques and tools to measure diffraction data out of a microcrystal are introduced.