Study Design: Cross-sectional study. Objectives: To describe experienced sitting-related health and stability problems among persons with paraplegia (PP) or tetraplegia (TP) and to investigate associations with personal, lesion and wheelchair characteristics as well as satisfaction with sitting posture. Setting: Dutch community. Methods: A self-report questionnaire on seating was developed and completed by wheelchair-users living with Spinal Cord Injury (SCI) for ≥10 years (N = 264). Sitting-related problems and satisfaction with sitting posture were compared between participants with PP and TP using Chi-square and t-tests. Logistic regression analyses were performed to investigate associated characteristics. Results: Reported sitting-related problems comprised: sitting to be tiring (regularly to always) (33%), sitting to be painful (28%), pressure ulcers in the last three months (29%), instability while sitting (8%) and instability during reaching (33%). Except for instability during reaching, no differences in occurrence of sitting-problems were found between lesion-group. Persons with TP were more dissatisfied with their sitting posture than persons with PP: 51% vs 36% (p = 0.022) and 51% and 47% respectively thought their sitting posture could be improved (p = 0.670). ‘Experienced lack of support in the wheelchair’ was associated with most sitting-problems. Pain and instability were associated with dissatisfaction with sitting posture. Conclusion: Sitting-related problems and dissatisfaction with sitting posture were frequently reported by persons with long-standing SCI. Sitting problems appeared to associate with lacking support in the wheelchair/seating. A comprehensive feedback from the wheelchair user and a stability check (reach task), as part of the wheelchair/seating-user fitting, may contribute to prevention of sitting-related problems.