The Environmental Radioactivity Laboratory of the UEx has carried out a study to quantify radioactive presence in fungi. According to the research, this quantification is made using transfer coefficients that compare the radioactive content in the receptor compartment (fungi) of the radioactive contamination, to that existing in the transmitter compartment (soil). From the study, we may conclude that fungi can be used when assessing the presence or absence of radioactive contamination in the soil.