Background and Purpose— Ultra-early blood pressure (BP) management in the prehospital setting could improve the efficacy of this treatment on attenuating intracerebral hemorrhage (ICH) expansion. We aimed to determine the association of prehospital systolic BP (SBP) with ICH volume, ultra-early hematoma growth, and the spot sign on admission. Methods— We conducted a retrospective study of a prospective database of 219 consecutive patients with spontaneous ICH admitted to the emergency department of a tertiary stroke center during a 3-year period. Prehospital SBP and ICH volume, ultra-early hematoma growth (ICH volume/onset-to-imaging time), and presence of the spot sign on admission were prospectively recorded. Primary outcome was ICH volume on admission. Secondary outcomes included ultra-early hematoma growth and frequency of the spot sign in patients scanned within 6 hours from symptom onset (hyperacute group). Results— Prehospital SBP was positively correlated with both SBP ( r =0.552; P <0.001) and ICH volume (ρ=0.189; P =0.006) on admission. Patients with ICH volume above the median value presented higher prehospital SBP (172.3±35.0 versus 163.7±27.8 mm Hg; P =0.049). This association remained significant in adjusted multiple logistic regression analysis (odds ratio, 1.01 for a 1-U increase in SBP; 95% confidence interval, 1.01–1.02; P =0.018). In the hyperacute group (n=126), prehospital SBP was unrelated to ultra-early hematoma growth (ρ=0.115; P =0.203) nor the presence of the spot sign (172.2±27.6 versus 171.8±31.6 mm Hg; P =0.959). Conclusions— Prehospital SBP is correlated with SBP on admission and independently associated with ICH volume on admission. These findings support the rationale of testing whether prehospital initiation of BP-lowering attenuates ICH expansion.