An analysis of the ground state of arsine is performed by using all the line assignments coming from a recent investigation of the vibrational system 2ν2/ν2+ ν4/2ν4/ν1/ν3at 1650–2350 cm−1. A set of 6837 ground state combination differences is used, in combination with all FIR and radio-wave and microwave data (RMW) available in the literature, to refine the ground state parameters. The rotational model takes into account all the nondiagonal contributions in 〈K|K± 3〉 and 〈K|K± 6〉, which are calculated via diagonalization, as well as the hyperfine interactions. The best estimates of the ground state parameters include 12 rotational and 4 quadrupole parameters. The overall rms deviation of the fit is 0.225 MHz for 7142 data fitted. The deviations for IR, FIR, and RMW data separately, are 0.329 × 10−3cm−1, 0.279 × 10−3cm−1, and 0.149 MHz, compared to average experimental uncertainties estimated to 0.5 × 10−3cm−1, 0.2 × 10−3cm−1, and 0.211 MHz for the three kinds of data, respectively. The parameters are compared to previous results and used for a prediction of the ground state energies up toJ= 20, including hyperfine structure. A list including calculated line frequencies and intensities for all the ground state rotational transitions obeying either ΔJ= 1, Δ|K| = 0, ΔF= 0, ± 1, or ΔJ= 0, Δ|K| = 0, ±3, ΔF= 0, ±1, is also produced up toJ= 20.