Objective: To evaluate whether early-onset severe preeclampsia prior to 34 weeks’ gestation is clinically different when associated with antiphospholipid antibodies. Design: A retrospective case-control study. Setting: Single university-affiliated tertiary referral center Population: 55 women with singleton pregnancies who delivered prior to 34 weeks’ gestation due to preeclampsia with severe features. Methods: Out of the 101 women with preeclampsia with severe features, the antiphospholipid antibodies status of 55 was available for analysis. The study group comprised 20 women with positive antiphospholipid antibodies (positive-aPL group), while the control group comprised 35 women without antiphospholipid antibodies (negative-aPL group). Main outcome measures: Obstetric and neonatal outcomes, laboratory results and pregnancy complications. Results: Positive-aPL women were hospitalized earlier (29, IQR 26.3–32, vs. 32, IQR 28-33 weeks gestation, p=0.05), gave birth at a significantly earlier gestational age (30, IQR 28.3-32.8 vs. 33, IQR 30-34, p=0.02) with a lower mean birth weight (1266.7±579.6 vs. 1567.3±539.7 grams, p=0.058) compared with negative-aPL women. Furthermore, platelet nadir was significantly lower for positive-aPL compared with negative-aPL women (97.2±49.7103/µL vs 141.3±61.13/µL, p<0.001) and maximal serum creatinine was higher (1.02±0.32 mg/dL vs. 0.92±0.13 mg/dL, p=0.03). Rates of neonatal complications were low and comparable between groups, although there was a trend for higher perinatal mortality among study group infants. Conclusions: The presence of antiphospholipid antibodies in women with early-onset preeclampsia with severe features is associated with earlier, more severe multi-organ involvement. Expedited screening for antiphospholipid antibodies in cases of early-onset severe preeclampsia may be considered.