The purpose of this study was to examine major factors that influence stream choice of femalernstudents in Medhanialem preparatory school in Addis Ababa. Mainly, it aimed to examine femalernstudents'stream choice in relation to 70:30 ratio. To achieve the objectives, data were collectedrnfrom 278 female students (176 from natural science and the remaining 102 from social sciencernstream), 48 teachers, two school principals and two guidance and counselors usingrnquestionnaires and interviews. The documents of students' enrollment across streams wererncollected from record office of the school under the study. The collected data throughrnquestionnaires and documents were analyzed in terms of percentage. The data collected throughrninterview were analyzed through narration. The analysis revealed that, even though there wasrnfluctuation, the total trend of female students' enrollment in natural science stream in sixrnconsecutive years is increasing and it seems in line with MOE (ESDP IV, 2010111). The findingsrnalso showed that, female students' stream choice was influenced by individual interest, lack ofrnguidance and counseling service, parentallguardian attitude, teachers ' attilude and societalrnal/itude. The effect of peers influence on female students' stream choice was not significant asrnthe study showed. The result obtained also showed that female students were placed against theirrninterest in natural science only to fulfill the requirement of 70: 30 ratio. Hence, attention need tornbe paid to: a) individual interest of female students while placing in different streams (b)rncreating awareness on 70:30 ratio to increase their enrollment in natural science by their willingrnand organizing campaign and celebrities at lower grades which involve different stakeholdersrn(c) improving overall contribution of guidance & counselors by aligning their plan with thernschool's developmental plan (d) motivating teachers by giving training and awarding those whornbetter contribute and encourage females' education. (e) Organizing natural science club at allrngrade levels.