AbstractBlack widow spider envenomation generally results in self-limiting pain that can be treated in the emergency department (ED) with analgesics and benzodiazepines, usually with no further intervention. Occasionally, a patient has to be admitted or treated with antivenom for refractory pain or a venom-induced complication. We present the case of an 84-year-old man who presented to our ED with chest pain and dyspnea after being bitten on the foot by a western black widow spider (Lactrodectus hesperus). His initial cardiac troponin I (cTnI) was elevated at 0.07 ng/ml and continued to rise to a peak of 0.17 ng/ml. He also had rhabdomyolysis, another uncommon complication of black widow envenomation. An elevated cTnI generally signifies myocardial injury and is rarely seen after black widow envenomation. We discuss the possible etiologies for an elevated cardiac biomarker, in this context, and review potentially serious complications of widow spider envenomation presenting with chest symptoms and an elevated cardiac biomarker.