The aim of this study was to evaluate the validity of platelet count (PC) and indices, including mean platelet volume (MPV), platelet distribution width (PDW) and platelet crit (PCT), in identifying the pregnancies at risk for preeclampsia. Demographic data and laboratory tests for PC, MPV, PDW and PCT of 250 pregnant women (100 normotensive pregnants, 121 pregnants with severe preeclampsia and 29 pregnants with mild preeclampsia) were retrospectively analyzed. Platelet counts and indices were compared between the study groups. MPV and PDW were significantly higher in preeclamptic pregnant women when compared to the normal group (p=0.006, p=0.046) and area under ROC curve for MPV was found statistically significant. PC, MPV and PCT were found significantly increased in late-onset preeclampsia (p<0.05) whereas there was no significant difference in these three indices in terms of severity of the disease. ROC analysis for MPV levels to differentiate earlyonset and late-onset preeclamptic cases was also found statistically significant. Measurement of MPV may contribute to identify the pregnants at risk for preeclampsia and assess the onset-time. PDW may be also useful in detection of the pregnant at risk for preeclampsia.