PURPOSE OF REVIEW: To summarize the current knowledge on the assessment of gastrointestinal dysfunction. RECENT FINDINGS: Clinical assessment is becoming more structured but remains largely subjective. Some instrumental tools to assess gastrointestinal motility have been developed but not yet widely applied in clinical practice. Imaging techniques offer a good method for static (i.e. nonfunctional) diagnostics but a standardized dynamic assessment at the bedside is currently unavailable. Recent studies on biomarkers have not provided convincing results for accurate evaluation of gastrointestinal function. SUMMARY: Clinical assessment remains the main tool for assessing gastrointestinal dysfunction. A single sign or symptom does not reflect gastrointestinal dysfunction adequately, and a set of variables might be needed. Studies on tools reflecting gastrointestinal motility and biomarkers for response to enteral nutrients, including absorption, are warranted.