The aim of this study is to identify the relationship between knowledge of primigravidae about labor and their level of fatigue during labor. The study was carried out in the antenatal clinic & labor & delivery unit at El-Shatby Maternity University Hospital in Alexandria where a quasi-experimental research design was adopted. A convenient sample of 60 primigravidae who accepted to participate in the study was involved in the study. They were divided equally into the experimental group for whom information about labor & fatigue was given & the control group for whom no information was given. A specially designed interview schedule was developed to assess the study subjects' knowledge about labor & fatigue. Then the content of eight hours teaching sessions was taught to the experimental group in the antenatal clinic by the researcher based on their needs. A modified fatigue symptoms checklist & the visual analogue scale were used to assess the women's levels of fatigue during labor. The study findings showed that women who had poor knowledge about labor & fatigue were more likely to suffer from severe level of fatigue during labor. The antenatal educational sessions, which were conducted by the researcher, had a positive influence on the majority of the study subjects' knowledge about labor and their levels of fatigue, as their knowledge had changed from poor to good & their level of fatigue was mild during labor.