We report on a male infant with a duplication 9p (pter----q13) and duplication 16p (p13----pter) resulting from a 3:1 meiotic disjunction of a maternal reciprocal translocation. In this case, the mode of segregation fits to the Pachytene-Diagram Model of Jalbert et al [1980]. The infant showed clinical features that have been described both in dup(16p) and in dup(9p). To our knowledge, this is the first time that this unbalanced karyotype has been reported.