We present a novel method ("waste") for the segmentation of text into tokens and sentences. Our approach makes use of a Hidden Markov Model for the detection of segment boundaries. Model parameters can be estimated from pre-segmented text which is widely available in the form of treebanks or aligned multi-lingual corpora. We formally define the waste boundary detection model and evaluate the system's performance on corpora from various languages as well as a small corpus of computer-mediated communication.