Although early mobilization of critically ill patients improves functional recovery, it is frequently hampered by tubes, drains, monitoring devices, and muscular weakness. When compared to standard care physiotherapy alone, a mobile treadmill with bodyweight support facilitates early mobilization and might shorten recovery time to independent ambulation. A single-center randomized controlled trial compared daily bodyweight supported treadmill training (BWSTT) to usual care physiotherapy in patients who had been or were mechanically ventilated (≥48 h) and had (≥MRC grade 2 quadriceps muscle strength. BWSTT included daily treadmill training and standard care physiotherapy (PT). The primary outcome was the time to independent ambulation in days, as measured by the Functional Ambulation Categories (FAC-score: 3). Hospital length of stay and serious adverse events were secondary outcomes. The median (IQR) time to independent ambulation in the BWSTT group (n=19) was 6 (3 to 9) days compared to 11 (7 to 23) days in the usual care group (n=21, P=0.063). The length of stay in the hospital was significantly shorter in the BWSTT group (P=0.037). There were no serious adverse events. BWSTT appears to be a promising intervention for improving ambulation recovery and decreasing hospital length of stay in ICU patients, justifying a sufficiently powered multicenter RCT.