The isotope Cd105 (55 min.) has been produced by the Ag107 (p,3n) reaction in the McGill University synchrocyclotron and has been investigated by means of a 180° spectrograph of high resolution, a lens spectrometer, and a scintillation spectrometer.The positron end point was found to be 1.691 ± 0.005 Mev. and the Fermi plot of the spectrum was straight down to about 800 kev. where a slight upward curvature began. Internal conversion lines found in the 180° spectrograph indicated γ-rays of energies 25.50, 27.69, 263.0, 292.5, 308.0, 312.1, 317.1, 320.5, 324.9, 336.3, 340.7, 347.0, 433.1, and 606.7 kev. High energy internal conversion lines found in the lens spectrometer beyond the end point of the positron spectrum were assigned to γ-rays of energies 1.908, 1.957, 1.995, 2.045, 2.277, and 2.318 Mev.In addition lines assigned to Ag105 have been recorded. These correspond to γ-rays of energies 64.0, 280.8, 319.4, 331.5, 344.9, 392.6, and 443.2 kev., of which that of 331.5 kev. has not been reported previously.