Atrial fibrillation, a major risk factor for stroke, is believed to occur first as paroxysmal episodes, gradually becoming more persistent, and finally progressing to chronic atrial fibrillation. Treatment of paroxysmal atrial fibrillation is an important target to prevent chronic atrial fibrillation. We describe a very unique case with postprandial hyperglycemia and obesity associated with drug-refractory paroxysmal atrial fibrillation. A 73-year-old Japanese woman with postprandial hyperglycemia suffered from drug-refractory paroxysmal atrial fibrillation. A 1600 kcal/day diet and walking three times/day for more than 30 min eliminated paroxysmal atrial fibrillation after 6 months. Diet and exercise should be considered as the initial therapy in patients with paroxysmal atrial fibrillation who also have postprandial hyperglycemia. This case suggests that postprandial hyperglycemia and insulin resistance might be one of the possible underlying mechanisms of paroxysmal atrial fibrillation.