This paper consists of a qualitative and quantitative study of scaled chrysophytes found in a peat bog of Tierra del Fuego, Argentina. Three taxa were identified: Mallomonas cyathellata var. chilensis Dúrrschmidt, M. striata Asmund and Synura sphagnicola (Korsh.) Korshikov; except for the last the others are new records for this kind of environment. Temperature and pH-range of these species are discussed.