Abstract. The Moon has been observed using the VATLY radio telescope at frequencies of 1420.4 and 1417.6 MHz in order to study the behaviour of the instrument in a domain of flux density close to the limit of its sensitivity. Drift scans have revealed a Moon flux density of 0.83 ± 0.16 kJy corresponding to a Moon black body temperature of 207 ± 40 K. From these results, a limit sensitivity of ∼ 300 Jy has been inferred in agreement with earlier coarser estimates.