Posttransplant lymphoproliferative disease is a complication of organ transplant with a myriad clinical and anatomic manifestations, thus making diagnosis difficult without histologic confirmation. In cases of lymphadenopathy confined to the abdomen, the diagnosis can be delayed because of late presentation and difficulty obtaining a tissue for histologic analyses. We describe the use of cross-sectional nuclear medicine imaging to locate enlarged abdominal lymph nodes; this facilitated minimally invasive laparoscopic lymph node excision biopsy to rapidly diagnose 2 cases of post-transplant lymphoproliferative disease. Prompt diagnosis has enabled early effective treatment, resulting in good patient outcomes.