Position affects the woman's anatomic and physiological adaptation to labor. For the second stage of labor an ideal position would open the pelvic outlet as widely as possible, provide a smooth path for the baby to descend through the birth canal, use the advantages of gravity to help the baby move down and give the mother a sense of the process. A Quasi experimental design was used in carrying out this study that aimed to assess the effect of maternal semi-sitting versus dorsal recumbent position on labor outcomes. It was carried out at the delivery unit of IsmailiaUniversityHospital. A representative sample of 200 women was recruited for this study according to certain criteria. The study subjects were equally divided into two equal groups, group I who assumed the semi-sitting position and group II who assumed the dorsal recumbent position. Data were collected through a structured interviewing schedule, and an observation checklist that were developed, validated and used to collect the necessary data. . The results revealed that group II had lower B.P (35.0%) compared to group I (3.0%). uterine contractions with an interval of 2 min., longer duration (>70-90 sec.) and severe intensity were significantly higher (89.0%, 93.0% and 95.0%) of group I respectively. Moreover, women they were more likely to push effectively (92.0%) of group I than group II (73.0%). Fetal heart rate below normal (15.0%) of group II compared to(3.0%)of group I .Spontaneous rupture of membrane was also higher (83.0%) among group I compared to (81.0%) of group II . Women in the group I had higher percentage of normal delivery (53.0%), and low percentage of episiotomy (25.0%) and perineal tear (22.0%) compared to group II (25.0%, 30.0% and 45.0% respectively). The mean duration of 2nd stage of labor was statistically higher (48.2±10.0) among group II than group I (42.3±8.5). Also mean neonatal Apgar score a statistically significant at first and fifth minutes among group I than group II. It is concluded that semi-sitting position had a significant effect on the improvement of labor outcomes. Thus it is recommended that birth attendant should be advised to deliver woman while she is in semi-sitting position instead of routine use of dorsal recumbent position during the second stage of labor.