A Fourier-transform absorption spectrum of the three silicium isotopes of silane in natural abundance have been recorded from 840 to 1040 cm−1. The line width is 3 × 10−3 cm−1 and the absolute accuracy is estimated to be about 2 × 10−4 cm−1 for non-saturated and non-overlapped lines. The analysis of this spectrum is achieved, using a Hamiltonian, formulated with an irreducible tensorial set in the Td group.For the dyad ν2 and ν4 and for each isotopic species, 30 reduced effective Hamiltonian parameters are determined, giving the line wave numbers with 2.5 × 10−4 cm−1 for 28SiH4, 3.4 × 10−4 cm−1 for 29SiH4, and 5.5 × 10−4 cm−1 for 30SiH4 as the standard deviation for J = 0–20.