Isolated internal iliac (hypogastric) artery aneurysms are sporadic. When they rupture, patients face a significant risk due to the deep‐seated location of the aneurysm within the pelvis region. Herein, we describe a rare case of an unruptured isolated internal iliac artery aneurysm measuring 4.1 × 4.0 × 3.2 cm found coincidentally in a routine female pelvic ultrasound. Considering the heightened risk of rupture, expeditious diagnosis and intervention are imperative.