Objective:To investigate the efficacy and effectiveness of albendazole and mebendazole in the treatment of Ascaris lumbricoides(A.lumbricoides) in the North-Western Indonesia.Methods: 229 primary school children who were positive for A.lumbricoides in their stool were recruited in the study.123 children received single-dose of 400 mg albendazole and 106 children received single-dose 500 mg of mebendazole.After 1 week,their stools were examined for the cure rate (CR) and egg reduction rate(ERR).Egg culture was also performed and observation was made on week-1,-3,-4.Results:have shown a non-significant difference in CR 96.7%vs.100%:and ERR of 99.3%vs.100.0%for albendazole and mebendazole groups respectively(P>0.05).In-vitro egg culture has shown trends of decrease in the percentage of the unfertilized eggs and in≥2 cell eggs in both treatment groups(P<0.05).The embryonated eggs from the albendazole groups has shown an increase from 7.3%on week-1 to 13.8%on week-4,whilst the mebendazole group has shown a constant increase during the whole 4 weeks of culture from 7.5%to 28.3%(P<0.01). Conclusions:No evidence of drug resistance is noted so far from the area of North-Western part of Indonesia.In addition,although both drugs showed incomplete ovicidal effects,single-dose albendazole is better than mebendazole in sterilizing A.lumbricoides eggs. Objective: To investigate the efficacy and effectiveness of albendazole and mebendazole in the treatment of Ascaris lumbricoides (A. imbricoides) in the North-Western Indonesia. Methods: 229 primary school children who were positive for A. lumbricoides in their stool were recruited in the study.123 children received single-dose of 400 mg albendazole and 106 children received single-dose 500 mg of mebendazole. After 1 week, their stools were examined for the cure rate (CR) and egg reduction rate (ERR). Egg culture was also performed and observed was made on week-1, -3, -4. Results: have shown a non-significant difference in CR 96.7% vs.100%: and ERR of 99.3% vs.100.0% for albendazole and mebendazole groups respectively (P> 0.05) .In-vitro egg culture has shown a decrease in the percentage of the unfertilized eggs and in ≧ 2 cell eggs in both treatment groups (P <0.05). The embryonated eggs from the albendazole groups have shown an increase from 7.3% on week-1 to 13.8% on week-4, whilst the mebendazole group has shown a constant increase during the whole 4 weeks of culture from 7.5% to 28.3% (P <0.01). Conclusions: No evidence of drug resistance is noted so far from the area of ​​North-Western part of Indonesia. In addition, Both both drugs showed incomplete ovicidal effects, single-dose albendazole is better than mebendazole in sterilizing A.lumbricoides eggs.