This protocol describes how to perform DNA FISH on dissected tissue of Planococcus citri. While the aim of this experiment was to distinguish localisation of the P. citri endosymbionts in ovarian and bacteriome tissue, the protocol can be easily adjusted for other tissues or the use of different probes.The probes used here were designed according to the works of von Dohlen et al. (Nature, 2001) and Lopez-Madrigal et al. (PLOS ONE, 2013).In brief, tissues were isolated in 1xPBS and transferred to various fixatives. After fixation samples were dehydrated and pre-incubated in hybridisation buffer before adding probes. After hybridisation, samples were washed and counter stained with Hoechst. FInally, stained tissues were transferred to microscopy slides, briefly air-dried and mounted in FLuorSave Reagent (Millipore).