Background <p>While electrical muscle stimulation during hemodialysis has been reported to&#xa0;improve physical performance in middle-aged patients, clinical evidence regarding its efficacy in older patients with frailty remains limited.</p> Methods <p>In this crossover trial, we randomly assigned 18 older patients (aged ≥ 65&#xa0;years) with frailty receiving maintenance hemodialysis in a 1:1 ratio&#xa0;to the study intervention. Group 1 underwent electrical muscle stimulation first, followed by a five-week washout period, and then the control session&#xa0;without electrical muscle stimulation. Group 2 received the control session first, followed by the electrical muscle stimulation sessions. Eligible patients had physical frailty defined by a Short Physical Performance Battery (SPPB) score of 4–9 points. Electrical muscle stimulation was conducted for 30–40&#xa0;min per day, 3&#xa0;days a week, over 5&#xa0;weeks, during hemodialysis sessions. The primary outcome was the difference in quadriceps isometric strength before and after the treatment period.</p> Results <p>Among 18 patients who were randomized, 16 patients were included in the intention-to-treat analysis (median age: 76&#xa0;years [Q1 to Q3, 72 to 79]; men: 38%; median SPPB: 6 points [Q1 to Q3, 5 to 9]). The median change in quadriceps isometric strength (Q1 to Q3) was 1.5%dry weight (%DW) (0.2 to 4.2) during the electrical muscle stimulation intervention period and − 3.6%DW (− 7.7 to − 1.6) during the control period (<i>P</i> = 0.0027).</p> Conclusions <p>Our trial found that intradialytic electrical muscle stimulation was associated with improved quadriceps isometric strength in older patients with frailty, indicating a potential benefit of intradialytic electrical muscle stimulation intervention for physical performance, also&#xa0;in these subjects.</p> Trial registration <p>The study was registered in a public trial registry (UMIN-CTR, number: UMIN000032501).</p> Graphical abstract <p></p>