The contribution of high-eccentricity trans-Neptunian objects to the observed populations of both short-period and long-period comets is estimated. About $10^{10}$ objects with a radius $R>0.7$ km in orbits with perihelion distances $28<q<35.5$ AU and semimajor axes $60<a<1000$ AU are the main source of Jupiter-family comets. If the population of high-eccentricity trans-Neptunian objects formed about 4.5 Gyr ago, the mean near-parabolic flux produced by these objects is on the order of 0.3-1.0 AU$^{-1}$ yr$^{-1}$ for comets with $R>0.7$ km.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html