Aim: It has been reported that red cell distribution width (ROW) and hypertension are somehow related, but there is no well-established evidence about the probable relationship between RDW and preeclampsia. The present study aimed to determine whether RDW in the first trimester can be used to predict the presence and severity of preeclampsia. Material and Method: This is a retrospective review of 57 healthy pregnant women, 42 women with mild preeclampsia, and 18 women with severe preeclampsia who delivered at the study center. These three groups were compared with respect to complete blood count parameters obtained during the first trimester. Results: When compared with the control group, systolic blood pressure, diastolic blood pressure, leukocyte count, RDW, blood urea nitrogen, and proteinuria were significantly higher in the severe preeclampsia group (respectively p<0.001, p<0.001, p=0.036, p<0.001, p<0.001, and p<0.001). The median RDW values of control, mild, and severe preeclampsia groups were 12.51% (range: 10.6-15.02%), 13.2% (range:10.45-15.5%), and 13.7% (range: 11.9%-14.7%). RDW was significantly higher In the severe preeclampsia group than in the control group (p<0.001) and mild preeclampsia group (p-0.001). However, mild preeclampsia and control groups had statistically similar RDW values (p>0.05). Discussion: Increased RDW in the first trimester can be utilized to predict severe preeclampsia, but RDW values do not seem to correlate with the severity of preeclampsia.