Objective: To establish the diagnostic utility of the platelet-lymphocyte ratio in pregnant women with preeclampsia. Methods: A case-control study was carried out at the Hospital Central “Dr. Urquinaona” Maracaibo, Venezuela. A total of 180 pregnant women were selected. Ninety preeclamptic women were included as the study group (group A) and a control group selected for their age and body mass index similar to the study group, which consisted of 90 healthy normotensive pregnant women (group B). The general characteristics, platelet-lymphocyte ratio values and diagnostic efficacy were determined. Results: Group A patients presented lower platelet and lymphocyte values compared to group B patients (p <0.001). However, no statistically significant differences were found in platelet-lymphocyte ratio between group A patients (115.2 ± 32.7) and group B patients (122.3 ± 23.8; p = 0, 0971). A cut-off value of the platelets-lymphocyte ratio of 117 presented a value below the curve of 0.57, the sensitivity of 47.8%, the specificity of 50.0%, the positive predictive value of 48.9%, and the negative predictive value of 52.2%, with a diagnostic accuracy of 48.9%. Conclusion: Platelet-lymphocyte ratio is not a useful tool in the diagnosis of preeclampsia, since patients with the syndrome present similar values to normotensive pregnant women. Keywords: Platelet-lymphocyte ratio, Preeclampsia, Diagnosis, Pregnancy.