Resumen
[EN] We present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay Lambda(+)(c) -> p eta' with eta' -> eta pi(+)pi(-), using a data sample cor- responding to an integrated luminosity of 981 fb(-1), collected by the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. A significant Lambda(+)(c) -> p eta' signal is observed for the first time with a signal significance of 5.4 sigma. The relative branching fraction with respect to the normalization mode Lambda(+)(c) -> pK(-) pi(+) is measured to be B(Lambda(+)(c) -> p eta')/B(Lambda(+)(c) -> pK(-) pi(+)) = (7.54 +/- 1.32 +/- 0.73) x 10(-3),