We present the first model-independent measurement of the absolute branching fraction of the Lambda(+)(c) -> pK(-)pi(+)decay using a data sample of 978 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The number of Lambda(+)(c) baryons is determined by reconstructing the recoiling D(*)(-)(p) over bar pi(+)system in events of the type e(+)e(-) -> D(*)(-)(p) over bar pi(+)Lambda(+)(c). The branching fraction is measured to be B(Lambda(+)(c) -> pK(-)pi(+)) = (6.84 +/- 0.24(-0.27)(+0.21))%, where the first and second uncertainties are statistical and systematic, respectively.