Total and inorganic arsenic (tAs and iAs) analysis of soils and house dust samples, collected pair-wise from 41 residences of general public in Japan, was carried out to estimate contributions of these non-dietary oral sources to total daily exposure level of iAs, an established human carcinogen. Total As concentration in the samples was determined after mixed acid digestion followed by ICP mass spectrometric (ICPMS) determination. Non-spectroscopic interference arising from residual carbon in the digest was successfully compensated by addition of 3% acetic acid to sample digest and standard solution. Concentration of iAs in soil and house dust samples (n=20 each) was measured by liquid chromatography- ICPMS after extraction with synthetic gastric juice. Median tAs concentration in soil (n=38) and house dust (n=40) was 10 and 2.5 mg/kg, respectively. Median iAs (AsIII+AsV) concentration was <0.01 and 0.24 mg/kg, respectively. Assuming that adult unintentionally ingest 50 mg each of soil and house dust, daily exposure level was estimated to be 0.0005 and 0.012 μg/day, respectively. When recently reported daily dietary iAs intake (mean of two estimates: 15.4 μg/day) is considered, contributions from soil and house dust to total daily oral exposure was estimated to be 0.003 and 0.08%, respectively. Soil and house dust ingestion, as well as inhalation exposure (estimated to be 0.02 μg/day), was found to be insignificant for total daily iAs exposure of Japanese.