Objective: Inhalant anesthetics may interfere with normal cerebrovascular autoregulation. It was therefore hypothesized that intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in isoflurane-aneshetized horses would be especially sensitive to body and head position due to the potential for large hydrostatic gradients between the brain and heart in this species. Methods: Anesthesia was induced and maintained in six clinically healthy, unmedicated geldings with 1.57% isoflurane in O₂; mechanical ventilation was used to maintain normocapnia. ICP was measured using a subarachnoid strain gauge transducer. Blood gases and carotid artery, right atrium, and airway pressures were also measured. Five body positions were studied in semi-randomized order: dorsal recumbency with head down (DR-HD), dorsal recumbency with head level (DR-HL), lateral recumbency (LR), sternal recumbency with head level (SR-HL), and sternal recumbency with head up (SR-HU). Data were analyzed using paired t-tests. Results: ICP and CPP values, respectively, are as follows (mmHg; mean±SD): 36±4, 55±18 (DR-HD); 34±6, 51±32 (DR-HU); 24±5, 48±4 (LR); 19±11, 87±12 (SR-HL); -14±7, 71±10 (SR-HU). Significant differences were found between all positions except for SR-HL vs. LR. Significant increases in CPP were observed only in sternal positions. Conclusions: ICP in isoflurane-anesthetized horses changes inversely with the brain-to-heart hydrostatic gradient. Dorsal recumbency may also cause increases in ICP irrespective of head position.