BACKGROUND: Asymptomatic blood pressure (BP) elevation may be associated with cerebral hemorrhage (CH); however, few studies have investigated this association. We aimed to evaluate BP elevation before CH in hemodialysis (HD) patients and elucidate its associated factors. METHODS: We reviewed HD patients treated for CH at our hospital between 2008 and 2019 (CH group). The control group comprised HD patients treated at Nagasaki Renal Center between 2011 and 2012. Data were obtained from medical records and three consecutive HD charts, made immediately before CH. HD1 was the session closest to onset, followed by HD2 and HD3. Systolic and mean BP were evaluated at the beginning of HD, and factors associated with BP elevation were investigated. RESULTS: The CH and control groups included 105 and 339 patients, respectively. Systolic and mean BP at HD1 were significantly higher than those at baseline (HD2 + HD3) in the CH group by 5 and 3 mmHg, respectively (P < 0.001). Multiple linear regression analysis showed that lower calcium levels were significantly associated with BP elevation in the CH group (P < 0.05). The CH group was sub-divided by June 2013; the latter group had lower calcium levels (9.2 mg/dL) and a marked systolic BP difference from baseline (+ 10 mmHg) compared with the former (9.5 mg/dL and - 4 mmHg). CONCLUSION: Asymptomatic BP elevation was observed in HD patients before CH; this elevation was associated with lower serum calcium levels and observed more frequently in the recent era. The precise mechanism underlying this effect remains unknown.