The use of electrical stimulation (ES) should be considered for treating nonhealing pressure ulcers (PUs), but optimal ES wound treatment protocols have yet to be established. A randomized, controlled, double-blind clinical study was conducted to evaluate the effects of cathodal and anodal high-voltage monophasic pulsed current (HVMPC) on periwound skin blood flow (PSBF) and size reduction of Stage 2 to Stage 4 PUs of at least 4 weeks' duration. Persons >18 years of age, hospitalized with neurological injuries, at high risk for PU development (Norton scale <14 points; Waterlow scale >15 points), and with at least 1 Stage 2 to Stage 4 PU were eligible to participate in the study. Persons with necrotic wounds, osteomyelitis, electronic or metal implants in the PU area, PUs in need of surgical intervention, acute wound inflammation, diabetes (HBA1c >7%), diabetic neuropathy, cancer, and/or allergies to standard wound treatments were excluded. Patients were randomly assigned to 1 of 3 groups: anodal (AG), cathodal (CG), or placebo (PG) ES. All groups received individualized PU prevention and standard wound care. In the PG, sham ES was applied; the AG and CG were treated with anodal and cathodal HVMPC, respectively (154 μs 100 Hz; 360 µC/second; 1.08 C/day), 50 minutes per day, 5 days per week, for a maximum of 8 weeks. PSBF was measured using laser Doppler flowmetry at baseline, week 2, and week 4, and wound surface area measurements were obtained and analyzed using a digitizer connected to a personal computer. Data analysis utilized the maximum-likelihood chi-squared test, the analysis of variance Kruskal-Wallis test, the Kruskal-Wallis post-hoc test, and Spearman's rank order correlation. Nonlinear approximation based on exponential function was used to calculate treatment time needed to reduce the wound area by 50%. In all tests, the level of significance was set at P ≤.05. Of the 61 participating patients, 20 were in the AG (mean age 53.2 ± 13.82 years), 21 in the CG (mean age 55.67 ± 17.83 years), and 20 in the PG (mean age 52.5 ± 13.18 years). PUs (baseline size range 1.01 cm2 to 59.57 cm2; duration 4 to 48 weeks) were most frequently located in the sacral region (73.77%) and classified as Stage 3 (62.29%). PSBF at week 2 was significantly higher in the AG and CG than in the PG (P <.05). Week 4 differences were not statistically significant. Wound percentage area reduction calculated at week 8 for the AG (64.10% ± 29.22%) and CG (74.06% ± 23.23%) were significantly different from PG ulcers (41.42% ± 27.88%; P = .0391 and P = .0024, respectively). In both ES groups, PSBF at week 4 and percent wound surface area reductions between weeks 4 and 8 were positively correlated, but only the AG correlation was statistically significant (P = .049). In this study, both ES modalities improved blood flow and wound area reduction rate. Studies examining optimal ES treatment times for healing to occur, the effect of comorbidities and baseline wound variables on ES outcomes, and the nature of the relationship between blood flow and healing are necessary.