Scintigraphic colonic transit measurement has emerged as a unique disease-related biomarker pertinent to drug development and personalized therapy. This surrogate offers reproducible and accurate performance across a spectrum of common colonic motility disorders, linking colonic transit measurements to biological processes and clinical end points. The pathobiologic validity, prognostic utility, performance characteristics, evidence-based linkage of therapeutic intervention with outcome, applicability across distinct pharmacodynamic profiles, and potential for individualizing patient management are all attributes of this gastrointestinal imaging paradigm. The cumulative evidence suggests that the integration of colonic transit measurement as a biomarker would accelerate the development and regulatory approval of therapeutic agents for the treatment of colonic dysmotility.