We present a case of a middle-aged Caucasian woman who developed acuteon top of chronic limb ischaemia secondary to thrombotic occlusion of a persistent sciatic artery (PSA). Timely investigation and treatment were instituted resulting in a favourable outcome. PSA is an uncommon congenital, developmental, arterial anomaly which can cause serious lower limb complications such as acute or critical limb ischaemia and amputation. As this condition is rarely encountered in regular clinical practice, and has a limb-threatening potential, it is important to be aware of its cause, presentation and management. We describe the embryologic aetiology of PSA and discuss different investigation modalities and treatment options.