A descriptive cross-sectional survey in 410 women in the reproductive age (15-45) in An Phu commune, Tuy Hoa city, Phu Yen province to assess the prevalence and the intensity of Soil-transmitted helminth (STH) includes Ascaris lumbricoides, Trichuris trichiura and hookworms infection from Kato-Katz examnination. Results showed the overall . prevalence of STH infection is 24.9 percent (the prevalence of ascaris lumbricoides, trichuris trichiura and hookworms is 11.9 percent,3.7 percent and 14.1 percent respectively). The prevalence of STH infection in rural areas is 27.6 percent, in coastal areas is 22.5 percent
especially the prevalence of hookworm in rural and coastal areas is 18.8 percent and 8.9 percent (p0.01). The prevalence of STH infection to married group is 31.2 percent, to unmarried group is 12.5 percent. The prevalence of STH infection to the pregnant women group (22.6 percent) is lower than the one of the notpregnant women group (32.4 percent), remarkably the prevalence of hookworm infection to the pregnant women group accounted for 16.13 percent. The average number of eggs per feces gram of ascaris lumbricoides, trichuris trichiura and hookworms is 205.3, 22.1, 203,1. The highest intensity is the age group 35 to 45 (ascaris lumbricoides: 378.8 EPG
trichuris trichiura: 50.9 EPG
hookworms: 406.1 EPG).