Latissimus dorsi (LD) is the broadest muscle of the back responsible for extension and adduction of shoulder. The authors report a case of isolated unilateral absence of the latissimus dorsi muscle observed during an ablative surgical procedure and flap reconstruction. The left LD muscle was completely absent in our patient and no tendon fibers belonging to this muscle could be observable on further dissection. The surrounding muscle anatomy was normal and in place suggesting a developmental etiology for its absence. Awareness of this possible variation is of importance in considering reconstructive options. Clin. Anat. 25:966–968, 2012. © 2012 Wiley Periodicals, Inc.