Cytogenetic studies of thyroid hyperplasias and adenomas have shown that besides cases with an apparently normal karyotype different groups of cytogenetic abnormalities exist. Herein we describe the cytogenetic analyses of two benign thyroid tumors with deletions of the short arm of chromosome 2. A similar case has been described previously. Besides the previously well-established subgroups, alterations of chromosome 2 may thus characterize a new cytogenetic subgroup of benign thyroid tumors.