To evaluate diagnostic performance of Neutrophil/lymphocyte ratio (NLR), Platelet to lymphocyte ratio (PLR) and platelecrit in the first and third trimester in preeclampsia. This was a single center case control study conducted between January 2015 and January 2021. Patients diagnosed with preeclampsia were assigned as study population. The preeclamptic patients were assigned into two groups based on gestational weeks at diagnosis. Patients diagnosed before 34th gestational weeks were categorized as early preeclampsia and whereas patients diagnosed after 34th gestational weeks as late preeclampsia. Receiver operating characteristics curve was used to assess diagnostic value of first and third trimester NLR, PLR and platelecrit in preeclampsia. Detection rate of each variable was assessed for a 10% false positive rate. NLR in the first trimester have highest sensitivity of 30% at a 90% specificity to detect early preeclampsia. The area under curve (AUC) for NLR was 0.742 respectively. The best cut off for 1st trimester NLR was 4.98. PLR and platelecrit yielded low diagnostic performance. NLR in the first trimester has a moderate predictive performance for early preeclampsia. PLR was not different in preeclamptic cases and controls and platelecrit yielded a low diagnostic performance for preeclampsia.