Kidney transplant recipients are vulnerable to infections, especially cytomegalovirus (CMV) disease. It is recommended that clinicians plan their prophylaxis and therapeutic regimens based on viral load testing. CMV viral load monitoring testing provides useful information for identifying virologic response and possible antiviral resistance. Due to the paucity of medical literature on guiding viral therapy in cases of CMV tissue disease with nondetectable serum viral load, we intend to provide physicians with evidence on how to guide medical therapy in these cases. A 49-year-old Hispanic male recipient of a kidney transplant from a cadaver donor presented to the emergency department with anorexia, asthenia, diarrhea, weight loss, and supraclavicular and mediastinal adenomegalies at 2 months post-transplantation. Both patients were serum IgG- and IgM-positive for CMV, which classified them as intermediate risk for developing CMV disease or tissue-invasive disease (donor-positive/recipient-positive [D+/R+]). The patient was induced with basiliximab and methylprednisolone and received maintenance therapy with tacrolimus, mycophenolic acid, and prednisone. Real-time polymerase chain reaction analyses were performed due to suspicion for BK virus, B19 parvovirus, Epstein-Barr virus, and CMV, with an undetectable viral load for all. A biopsy specimen taken from the gastrointestinal tract confirmed CMV infection, which was corroborated through immunocytochemistry. Histopathologic testing is a possible option for patients with CMV tissue disease symptoms but no detectable serum viral load. Clinical observation is fundamental when viral monitoring is difficult.