[Purpose] We report the case of a pediatric patient with congenital lymphedema treated with complex decongestive physical therapy and low-level laser therapy. [Subjects and Methods] The patient was a 2 year-old girl who had lymphedema in the left upper limb since birth. Complex decongestive physical therapy and low-level laser therapy were administered for 7 sessions. [Results] The circumferences of the middle of the forearm, elbow joint, wrist, and hand of the left upper limb decreased 0.5, 3, 0.5, and 2 cm, respectively. The moisture content of the left upper limb decreased 70 mL (6.66%), while moisture ratio increased by 0.007%. [Conclusion] Complex decongestive physical therapy and low-level laser therapy are effective for reducing lymphedema in pediatric patients.