The study was conducted by using Kato-Kart method in feces analysis with the 688 samples of among three primary schools of Haiphong. The results were shown that: The overall worm infestation prevalence was 12.06 percent, Ascariasis rate 8.58 percent, Trichuriasis rate was 4.51 percent, hookworm accounted for 0.44 percent. Rate infected 1 worm was 10.61 percent
infected 2 worms was 1.45 percent. Low-intensity worm infestation: Ascaris lumbricoides 95.47 + or - 15.98 eggs/g feces
Trichuris trichura 34.91 + or - 9.26 eggs/g feces. Group with inappropriate practice such as often eating raw vegetables, do not wash their hands before eating and after using the toilet, not regular nail clippers had higher risk of intestinal worm infestation rate than that of group did not, the difference was statistically significant with p 0.05 (2.4 OR 2.7).