To verify whether trunk control test (TCT) upon admission to intensive inpatient post-stroke rehabilitation, combined with other confounding variables, is independently associated with discharge mBI. Multicentric retrospective observational cohort study. Two Italian inpatient rehabilitation units. A total of 220 post-stroke adult patients, within 30 days from the acute event, were consecutively enrolled. Not applicable. The outcome measure considered was the modified Barthel Index (mBI), one of the most widely recommended tools for assessing stroke rehabilitation functional outcomes. All variables collected at admission and significantly associated with mBI at discharge in the univariate analysis (TCT, mBI at admission, pre-stroke modified Rankin Scale mRS, sex, age, communication ability, time from the event, Cumulative Illness Rating Scale, bladder catheter, and pressure ulcers) entered the multivariate analysis. TCT, mBI at admission, premorbid disability (mRS), communication ability and pressure ulcers (P<.001) independently predicted discharge mBI (adjusted R =68.5%). Concerning the role of TCT, the model with all covariates and without TCT presented an R of 65.1%. On the other side, the model with the TCT only presented an R of 53.1%. Finally, with the inclusion of both TCT and all covariates, the model showed an R increase up to 68.5%. TCT, with other features suggesting functional/clinical complexity, collected upon admission to post-acute intensive inpatient stroke rehabilitation, independently predicted discharge mBI.