Entamoeba invadens is an ameba that parasites reptiles; it is very similar in morphology and physiology to Entamoeba histolytica. Due to this, it is used as an - experimental model for amebiasis research, specially in the differentiation process, since E. invadens can be induced to “in vitro” encystment, which is not possible — with E. histolytica.Chromatoid bodies, are arrays of helical structures formed by the aggregation of ribosomes, that are found only in cystic forms of E. invadens, in trophozoites cultured in slow growing conditions, or in the presence of protein synthesis inhibitors. This paper reports the formation of chromatoid bodies in trophozoites of E. invadens in active growing phase and high CO2 tension.