The gas-phase electronic spectrum of the 1,3-cyclopentadiene radical cation (C5H6+) has been investigated using resonance-enhanced photodissociation of mass-selected C5H6+ Ar complexes in a tandem mass spectrometer. The D-1(B-2(1),) D-0((2)A(2)) band system spans the 460-620 nm range, while the D-2(2B1) 4 Do(2A2) band system appears between 320 and 370 nm. The band origins for the two systems are estimated to occur at 16 560 +/- 25 and 27 808 + 25 cm(-1), respectively. The D, 4 Do band system exhibits a distinctive series of broad peaks, which, with the aid of molecular vibrational frequencies and geometries calculated using time-dependent density functional theory, are assigned to progressions in totally symmetric ring deformation modes. The broadening arises from the Franck Condon activity of low-frequency out-ofplane vibrational modes, unresolved rotational contours, and possibly homogeneous lifetime broadening caused by rapid internal conversion to the ground electronic state.