Seven patients receiving systemic chemotherapy for solid tumors developed an erythematous papulosquamous eruption resembling a drug eruption in sun-exposed areas. Careful examination revealed that the lesions were actually inflamed actinic keratoses. Biopsies of typical lesions in three of the patients confirmed this clinical impression. While one patient was receiving systemic 5-fluorouracil alone, and three were receiving 5-fluorouracil and cisplatin, three others developed inflammatory flares of actinic keratoses while receiving other chemotherapeutic drugs. One patient received doxorubicin and vincristine, one received doxorubicin alone, and one received the combination of dactinomycin, vincristine, and decarbazine. Since this phenomenon appears to be due to the effect of chemotherapy on the atypical keratinocytes present in actinic keratoses, discontinuation of the chemotherapy is not indicated in this situation.