Trichomonads are protists found in several environments. Some of them are parasites, whereas the others live in the gut without provoking any apparent infection. Among the most studied are the parasites Trichomonas vaginalis and Tritrichomonas foetus, that infect the urogenital tract of humans and cattle, respectively. The cytoskeleton of the trichomonad group is composed of rootlets of proteinaceous structures, many of which have not yet been characterized. Among the main structures are: the pelta-axostyle system made of microtubules; the costa, a periodic rootlet; the parabasal filaments, located close to the Golgi complex and several other filaments whose functions are completely unknown. Some studies indicated that the axostyle participates in karyokinesis, the costa supports the flagellar movements of the recurrent flagellum and the nucleus has a defined position due to fibrils that perform an anchoring system. The flagellar canal is supported by the pelta, a microtubular structure. Membrane-skeleton interactions have been described in the overall matrix filling the cytoplasm, in the Golgi complex, in the hydrogenosomes and other cell structures, on the nuclear envelope at mitosis, interphase and in the nucleoplasm. Different techniques such as plasma membrane extraction, whole mount cell procedures, field emission scanning electron microscopy (FESEM), the cell-sandwich technique, freeze-etching and cytochemistry have been used in the studies of trichomonad cytoskeleton. A labile version of the cytoskeleton was demonstrated in this protozoan. It is composed by an array of filaments of distinct diameters resembling the conventional image of a network-like cytoskeleton typical from other eukaryotic cells.