The aim of the study was to jointly analyze temperature-induced changes in low-threshold single motor unit twitch torque and action potential properties. Joint torque, multi-channel surface, and intramuscular electromyographic (EMG) signals were recorded from the tibialis anterior muscle of 12 subjects who were instructed to identify the activity of a target motor unit using intramuscular EMG signals as feedback. The target motor unit was activated at the minimum stable discharge rate in seven 3-min long contractions. The first three contractions (C1-C3) were performed at 33°C skin temperature. After 5 min, the subject performed three contractions at 33°C (T1), 39°C (T2), and 45°C (T3), followed by a contraction at 33°C (C4) skin temperature. Twitch torque and multi-channel surface action potential of the target motor unit were obtained by spike-triggered averaging. Discharge rate (mean ± SE, 7.1 ± 0.5 pps), interpulse interval variability (35.8 ± 9.2 %), and recruitment threshold (4.5 ± 0.4 % of the maximal voluntary torque) were not different among the seven contractions. None of the investigated variables were different among C1-C3, T1, and C4. Conduction velocity and peak twitch torque increased with temperature (P < 0.05; T1: 3.53 ± 0.21 m/s and 0.82 ± 0.23 mNm, T2: 3.93 ± 0.24 m/s and 1.17 ± 0.36 mNm, T3: 4.35 ± 0.25 m/s and 1.46 ± 0.40 mNm). Twitch time-topeak and surface action potential peak-to-peak amplitude were smaller in T3 (61.8 ± 2.0 ms and 27.4 ± 5.1 µV) than in T1 (71.9 ± 4.1 ms and 35.0 ± 6.5 µV) (P < 0.05). The relative increase in conduction velocity between T1 and T3 was positively correlated (P < 0.05) with the increase in twitch peak amplitude (r² = 0.48), with the decrease in twitch time-to-peak (r² = 0.43), and with the decrease in action potential amplitude (r² = 0.50). In conclusion, temperature-induced modifications in fiber membrane conduction properties may have a direct effect on contractile motor unit properties.