We study the problem of scheduling jobs on a serial batching machineto minimize total tardiness. Jobs of the same batch start and arecompleted simultaneously and the length of a batch equals the sum ofthe processing times of its jobs. When a new batch starts, a constantsetup time s occurs. This problem 1| s-batch| ∑Ti isknown to be NP-Hard in the ordinary sense. In this paper we show thatit is solvable in pseudopolynomial time by dynamic programming.