Study design: Observational study Objective: To describe body mass index (BMI) during rehabilitation in people with a newly sustained spinal cord injury (SCI). Setting: Inpatient SCI rehabilitation in Denmark. Participants: Inpatients, >18 years, having sustained a SCI within the last 12 months at admission to primary rehabilitation, inclusive of various SCI etiology, neurological level, completeness of the lesion or mobility status. Methods: Measures of BMI were obtained at admission and discharge as part of standard care. At one SCI center measures of BMI were sampled at follow up 9.5 months after discharge as well. BMI was described by mean and standard deviation (SD). Paired t-test was used to test difference in BMI between admission and discharge. Repeated measures Analysis of Variance (ANOVA) was used for analyzing BMI deriving from three time points. Results: Overall BMI was stable with no change (25.4 kg/m² at admission and 25.6 kg/m² at discharge) during rehabilitation at the two national centers. In participants with an American Spinal Injury Association (ASIA) Impairment Scale (AIS) D classification, BMI was higher during rehabilitation compared to the other groups and increased significantly (p = 0.008) from discharge to follow up. Conclusions: Overall BMI was stable but higher than recommended in people with SCI undergoing rehabilitation at the two national centers in Denmark. Participants with an AIS D SCI were obese according to SCI adjusted BMI and the World Health Organization (WHO) recommendations during rehabilitation and at follow up.