We report two adult patients with Philadelphia chromosome positive (Ph+) B-cell acute lymphoblastic leukemia (ALL) who presented an additional dic(16;18)(q11;p11) that, to the best of our knowledge, has never been previously reported. Fluorescence in situ hybridization analysis confirmed the translocation and showed it to be dicentric. Both patients were treated for the ALL, but showed refractory disease and died despite aggressive treatment. Similarly to what has been reported with other additional chromosome abnormalities, our cases suggest that the presence of this novel translocation confers an adverse effect to the already poor prognosis of Ph+ ALL.