Measuring ankle torque is of paramount importance. This study compared the test–retest reliability of the plantar flexion torque–generating capacity between older and younger men. Twenty-one older (68 ± 6 years) and 22 younger (25 ± 5 years) men were tested twice for maximal isometric plantar flexion. Peak torque (PT), rate of torque development, and contractile impulses (CI) were obtained from 0 to 50 ms (rate of torque development_0–50; CI_0–50) and from 100 to 200 ms (rate of torque development_100–200; CI_100–200). Typical error as the coefficient of variation (CV_TE) and intraclass correlation coefficient were used to assess test–retest reliability. Student’s t test was applied to investigate systematic errors. The CV_TE ratio was used for between-group comparisons. Only PT demonstrated acceptable reliability (intraclass correlation coefficient ≥ .75 and CV ≤ 10%). Older men demonstrated greater CV_TE than younger men for PT (ratio = 2.24), but lesser for rapid torque (ratio ≤ 0.84). Younger men demonstrated systematic error for PT (6.5%) and CI_100–200 (−8.9%). In conclusion, older men demonstrated greater variability for maximal torque output, but lesser for rapid torque.