The prevalence of ascariasis in Indonesia remains high, especially in children who live in crowded area. Knowledge on A. lumbricoides is the key in preventing ascariasis. The purpose ofthis research is to know the effectiveness of health education in increasing the knowledge on thelife cycle of A. lumbricoides among the orphans. This experimental study (pre-post study) wasconducted at orphanage in Lubang Buaya Village, East Jakarta. The data was taken on June, 122012 by handing out questionnaires about the life cycle of A.lumbricoides to the subjects before andafter health education. All orphans who gathered were becoming the research subjects. Data wasprocessed using SPSS 11.5 and tested with marginal homogeneity. The results show the numbersmale subjects and female subjects are 59 (41.5%) and 83 (58.5%), 78 primary school (54.9%),55 junior highschool (38.7%), and 9 senior highschool students(6.4%). Before health education,the numbers of respondents with good, fair, and poor knowledge level of A. lumbricoides were 1(0.7%), 11 (7.7%), 130 subjects (91.6%). After education, the number of subjects with good andfair knowledge increased to 8 (5.6%) and 50 subjects (35.2%), while poor knowledge decreasedto 84 (59.2%). Marginal homogeneity test showed a significant difference (p<0.001) between theorphans’ knowledge before and after health education. In conclusion, health education is effectiveto increase knowledge of A. lumbricoides in orphans.Keywords: knowledge level, health education, orphans, ascariasis.