The beam-foil technique is applied to study the spectra of As III-V in the wavelength range 300 to 2000 AA. Fifteen new transitions are assigned to As V, involving the classification of eight new levels. From the 4s, 5s, 6s and 4p, 5p, 6p levels the As V ionisation potential is found to be 62.76+or-0.06 eV. Lifetimes and multiplet f values are reported from transitions from the 4s24d and 4s4p2 2D terms of As III, the 4s5s and 4p2 1S, 4p2 1D, 4s4p1P0 and 4s4d3D terms of As IV, and the 4p2P0, 4d2D and 5s2S terms of As V. Arbitrarily normalised decay curve (ANDC) analyses were used to overcome the problems associated with cascade repopulation in the cases of the 4s4p1P0 (As IV) and 4p2P0 (As V) terms. The resulting multiplet f value for the As V resonance transition is in good agreement with theory, but that for the As IV resonance transition is about 20% below theory, possibly due to omission from the ANDC analysis of the cascade from 4s4d1D, which is yet to be assigned.