In patients with stable coronary artery disease, percutaneous coronary intervention is associated with improved outcomes if the lesion is deemed significant by invasive functional assessment using fractional flow reserve. Recent studies have shown that a revascularization strategy using instantaneous wave-free ratio is noninferior to fractional flow reserve in patients with intermediate-grade stenoses. The decision to perform coronary artery bypass grafting surgery is usually based on anatomic assessment of stenosis severity by coronary angiography. The data on the role of invasive functional assessment in guiding surgical revascularization are limited. In this review, we discuss the diagnostic and prognostic significance of invasive functional assessment in patients considered for coronary artery bypass grafting. In addition, we critically discuss ongoing and future clinical trials on the role of invasive functional assessment in surgical revascularization.