We present the cytogenetic, interphase fluorescence in-situ hybridization (FISH) and DNA content findings in a clinically aggressive adenoid cystic carcinoma (ADCC) of the parotid gland. The tumor manifested diploid chromosomal and DNA content by cytogenetic, interphase FISH and flow cytometry. G-banding analysis revealed inv(5)(p15.2q33) and t(6;15)(q25;q15) as the only structural alterations in all 30 metaphases examined. The limited structural abnormalities found in this recurrent lesion suggest that they may constitute a primary or early event in the development of this tumor. The involvement of 6q region in our tumor and in some of the previously reported ADCC supports the association between this region and the evolution of at least a subset of these tumors.