Asymptomatic exogenous lipoid pneumonia (ELP) is rarely reported in Japan where liquid paraffin is seldom used as a laxative. Here we report a Japanese patient with asymptomatic ELP incidentally detected by annual examination. A 72-year-old man accidentally sprayed home-use pesticide aerosol toward his face, but symptoms like cough and dyspnea did not follow. A few days later chest X-ray performed as part of an annual health examination detected bilateral consolidation. He was referred to our department. Pathological examination, including lipid stain, of transbronchial lung biopsy obtained from right-sided B⁴a and B⁸a showed numerous lipid particles and lipid-laden macrophages in alveolar spaces and the interstitium, leading to the diagnosis of exogenous lipoid pneumonia. Since pyrethroids, the active ingredient of the pesticide, are recognized as safe for humans, the causative agent seemed to be a petroleum solvent such as kerosene. We should be aware that pesticide-induced lipoid pneumonia can present as an asymptomatic chest X-ray abnormality. Moreover, caution should be exercised when performing lipid stain so as not to dissolve the lipids in the process of deparaffinization for hematoxylin-eosin (HE) staining.