This study describes dendritic cells in thyroid sections of iodine deficient goiters. Cells were characterized by monoclonal markers and detected by immunohistochemistry and double labelling immunofluorescence. We observed dendritic cells located in focal aggregates in the interstitium and epitheloid cells as well as multinucleated giant cells filling thyroid follicles. All these cells showed strong positivity for the MHC class II molecules HLA-DR, -DQ, -DP and RFD1, a monoclonal marker for active antigen presenting cells.