OBJECTIVES: Crohn's disease is a chronic inflammatory bowel disease. Severe Crohn’s disease management includes anti-Tumor Necrosis Factor (anti-TNF) drugs differing from treatments used in early stages in terms of efficacy, safety and convenience. To understand how specificities of anti-TNF treatments are perceived by patients, the Satisfaction for Patients in Crohn's disease (SPACE) questionnaire was developed to measure satisfaction with anti-TNF treatment in patients with severe Crohn's disease. The study objectives were to finalise and psychometrically validate the SPACE questionnaire. METHODS: An observational, longitudinal, multicentre study was conducted in patients with severe, active Crohn's disease for which anti-TNF therapy was indicated. The 62-item pilot version of the SPACE questionnaire was completed by patients at inclusion, 12 and 13 weeks after first anti-TNF injection. The final structure (i.e. grouping of items into dimensions) was defined using multitrait and regression analyses. Psychometric validation of final SPACE scores included clinical validity (against Harvey-Bradshaw score), concurrent validity (against Treatment Satisfaction Questionnaire for Medication –TSQM–), internal consistency reliability, test-retest reliability and responsiveness. RESULTS: The main population included 279 patients (mean age=36, 56% female). Quality of completion was good (55-67% of patients with no missing items). Four items were little informative and thus removed from the final questionnaire. Eleven scores were defined: disease control, three transition scales (non-anal symptoms, anal symptoms, quality of life), side-effects, treatment convenience, three expectation disconfirmation scales (efficacy, side-effects, convenience), satisfaction with treatment, and motivation. Psychometric scores matched standards for clinical validity (better perception for patients with less severe disease), concurrent validity (e.g. correlation between SPACE satisfaction with treatment and TSQM satisfaction scores=0.59), internal consistency reliability (Cronbach’s alphas=0.67-0.93), test-retest reliability (intraclass correlations=0.62-0.91), and responsiveness (better perception improvement for improved patients). CONCLUSIONS: The SPACE questionnaire is a valid, reliable and responsive instrument to measure patients’ satisfaction with anti-TNF treatment in severe Crohn's disease.