A catalog of a sample of 105 Jupiter family (JF) comets (defined as those with Tisserand constants T>2 and orbital periods P<20yr) is presented with our ``best estimates'' of their absolute nuclear magnitudes H_N_=V(1,0,0). The catalog includes all the nuclear magnitudes reported after 1950 until August 1998 that appear in the International Comet Quarterly Archive of Cometary Photometric Data, the Minor Planet Center (MPC) data base, IAU Circulars, International Comet Quarterly, and a few papers devoted to some particular comets, together with our own observations. Photometric data previous to 1990 have mainly been taken from the Comet Light Curve Catalogue (CLICC) compiled by Kamel (1991, The comet light curve catalogue/atlas. I. The compiled observations. Uppsala Univ. Reprocentralen HSC). Most absolute nuclear magnitudes are found in the range 15-18, with no magnitudes fainter than H_N_~19.5.