The prevalence of helminthic infections was surveyed on a total of 6,178 residents (males 2,549 and females 3,629) in 102 villages of 9 provinces in Lao PDR between 2007 and 2011 under the project of the Lao Ministry of Health and the Japan International Cooperation Agency (JICA). The survey revealed that the overall prevalence of helminthic infections was 34.6% (2,143/6,178). The most prevalent helminthic infections were hookworms (21.1%), followed by Opisthorchis (6.4%), Haplorchis (5.4%), and Phaneropsolus (1.4%). The prevalence of helminthic infections was significantly higher in rural areas (40.1%) than in urban areas (14.1%). The survey also revealed that the prevalence of helminthic infections was higher in males (36.4%) than in females (32.9%). The results of this survey suggest that helminthic infections are still a significant public health problem in Lao PDR, particularly in rural areas. Therefore, control measures should be implemented to reduce the prevalence of helminthic infections in these areas.