A 23-year-old woman presented with diarrhea, flaccid quadriparesis, a low serum potassium level, and an elevated creatine kinase level. A stool culture yielded Yersinia enterocolitica, and a muscle biopsy was compatible with a hypokalemic myopathy. The patient's diarrhea responded to sulfamethoxazole and trimethoprim therapy. We suggest that Y enterocolitica be added to the group of intestinal pathogens capable of producing hypokalemia and rhabdomyolysis.