The present study was designed to elucidate the recent prevalence of the intestinal protozoa and to demonstrate the relationship on prevalence of the surveyed population with their academic career and living conditions. During the period from May to July 1981, total 2, 735 fecal specimens were collected from the inhabitants of 11 areas in Gyeong-gi Do(province) near by Seoul City, and 6 areas in Jeonra Bug Do, southwestern part of Korea. The samples were fixed with SAF solution and were examined by formalin-ether sedimentation technique. The results are summarised as follows: 1, Overall positive rate of intestinal protozoa was 11. l% : Gyeong-gi Do, 10.7%; Jeonra Bug Do, 11.7%. 2. Five species of intestinal protozoa were detected: Entamoeba histolytica 0.69% : Entamoeba cali 5.52%; Endolimax nana 2.71%, Giardia lamblia 2.23%; lodamoeba biitschlii 0.18%. 3. Highest positive rates among the examined areas were recognized: Incheon City of Gyeong-gi Do, 26.7%; Im-sil Gun(county) of Jeonra Bug Do, 19.9%. 4. By species, E. nana showed the highest prevalence rate (13.74%) in Incheon City, and E. histolytica (2.37%) and E. coli (9.95%) in Im-sil Gun. 5. Prevalence of E. histolytica in rural areas was higher than in urban areas. 6. No significant difference in the prevalence rate by sect and age was recognized, although the group under 10 years and over 60 years were lower than in other age groups. 7, The highest positive rate of E. histolytica was observed in pauper group and significant linearity of prevalence rate of E. histozytica by monthly income was observed. 8. The inhabitants who used conventional latrine showed higher prevalence, 11.5%, than the group of inhabitants who used modified privy. 9. Although no significant difference of positive rate was recognized by academic career, but the lowest prevalence rate was observed in college graduates. 10. Over half of the surveyed population, 64.8% has no experience on anthelmintic practice. Number of anthelmintic application resulted no difference in prevalence. In conclusion, prevalences of intestinal protozoa in Gyeong-gi Do and Jeonra Bug Do decreased remarkably in comparison with those of one decade before. However, economic level, academic career and anthelmintic administration seemed no essential reasons for such declination.