A 52-year-old woman with advanced non-small cell lung cancer was admitted to our hospital with melena and palpable purpura which appeared on her lower legs. She had been taking gefitinib for about 2 months before admission. A skin biopsy revealed leukocytoclastic vasculitis in the superficial dermis and immunofluorescence also showed the presence of C3 depositions within the blood vessel walls, which led to a diagnosis of Henoch-Schönlein purpura. The purpura gradually improved with topical steroids and bed rest; however, gefitinib had to be discontinued because of a growing papulopustular rash with intense itching, and as a result of the discontinuation, both types of skin lesions resolved. Two months later, she resumed gefitinib treatment since her level of CEA began to rise. Even though the papulopustular rash developed after the readministration of gefitinib, there had been no evidence of Henoch-Schönlein purpura recurrence during 2.5 years follow-up. It has been reported that adult onset Henoch-Schönlein purpura is often associated with malignancy. This case, however, suggests that not only drug eruption but also paraneoplastic vasculitis should be considered in the differential diagnosis of palpable purpura in patients with non-small cell lung cancer receiving treatment with gefitinib.