Only four cases of chordoma have been described cytogenetically. We report the cytogenetic findings of a fifth case. Chromosome analysis of a primary sacral chordoma from a 69-year-old man showed the following chromosome complement: 43,XY,-2,-3,del(4)(q32),-6,+7,-11,der(12)t(9;12)(q12;p11),add(16)(q23),- 20,add(22)(q13),+mar.