Background <p>Preeclampsia is a multisystem disorder and is one of the leading causes of maternal and perinatal morbidity and mortality worldwide, particularly in developing countries like Ethiopia. Therefore, this study aim to asses the prevalence and feto-maternal outcome of early onset of preeclampsia and late onset of Preeclamsia in selected hospitals in Nekemte City.</p> Materials and Methods <p>A Facility-based prospective cohort study was conducted at Wallaga University compressive specialized Hospital from December 2024 to June 2025. A total of 104 pregnant women with Preeclampsia were recruited for this study. Data were entered into Epi Info version 3.1, transferred, and analyzed using SPSS version 27.0. Categorical variables are presented as frequencies and percentages. Differences between the early-onset and late-onset groups were assessed using the Chi-square test. For tables with small expected cell counts (&lt;5), Fisher’s Exact test was employed. P-value &lt; 0.05 was considered statistically significant.</p> Result <p>Late-onset preeclampsia was significantly more prevalent than early-onset (70.2% vs. 29.8%, p&lt;0.001). Infants in the early-onset group had significantly lower birth weights and poorer Apgar scores at 1 and 5 minutes (all p&lt;0.05). Gestational age at delivery was a critical factor for neonatal survival (p&lt;0.001), with all cases of intrauterine and neonatal death occurring in the early-onset group. The mode of delivery and rates of major maternal complications did not differ significantly between the two groups. Most women in both groups showed improvement and were discharged.</p> Conclusion <p>This study confirms that early-onset preeclampsia, though less common, carries significantly higher risks of adverse neonatal outcomes, including mortality, compared to late-onset preeclampsia. We recommend enhanced fetal monitoring and delivery planning at advanced care facilities for early-onset cases to improve survival. </p>