Introduction. This protocol makes it possible to determine the chromosome number of banana clones in root tip squashes. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials, and the four steps of the protocol used for the chromosome counts (root sampling and treatment, slide preparation, observation of useful cells and chromosome counts on useful cells). Possible troubleshooting is discussed. Results. The protocol usually results in condensed and intensely stained chromosomes.