Background <p>Intensive care unit acquired-weakness syndrome (ICUAWS) leaves several complications in functional movements of patients such as severe walking disability.</p> Objective <p>Assessment of functional outcomes of 1-month inspiratory muscle training (IMT) in elderly with ICUAWS and severe walking disability was our aim.</p> <p>The design, setting, participants, and intervention.</p> <p>This study is a randomized controlled trial. ICUAWS patients who complained of severe walking disability on the Modified Functional Ambulatory Category Test (MFACT) were randomly assigned into the IMT group or control group, <i>n</i> = 20 for each group. Both groups received the traditional physical therapy program.</p> Results <p>The results showed that the post-therapy between-group comparison of ICUAWS sufferers/groups’ parameters showed a significant improvement toward the IMT group in six-minute walk test, inspiratory and expiratory muscle strength, forced vital capacity, time up and go test, 10-m walk test, forced expiratory volume in the first second, 30-s sit-to-stand test, partial pressure of arterial blood oxygen and carbon dioxide, MFACT, oxygen saturation of arterial blood, physical, and mental summary of short form 36.</p> Conclusion <p>In conclusion, IMT improves functional outcomes in ICUAWS patients with walking disability.</p> Trial registration number <p>The clinical trial ID of this ICUAWS trial is NCT06210763.</p>