Giant splenic artery aneurysms (GSAAs) larger than 8 cm in diameter have rarely been reported, particularly in older people. They are clinically important lesions, often asymptomatic and related to an increased risk of complications such as abrupt rupture, requiring emergency surgical treatment. Comprehensive geriatric assessment (CGA), originally developed for multidimensional clinical evaluation in several geriatric settings, was recently proposed as a fundamental preoperative aid for treatment planning of older patients undergoing elective surgery and preventing adverse post-operative outcomes. We present the first case of an asymptomatic 9-cm partially thrombosed GSAA, accidentally diagnosed during abdominal ultrasound in a 63-year-old woman from the Apulia region in Southern Italy. She successfully underwent aneurysmectomy, highlighting the usefulness of CGA in elective surgical patients.