The degradation rates of different mRNAs in higher plants can vary over a broad range and are regulated by a variety of endogenous and exogenous stimuli. During the past several years, efforts to better understand the control of mRNA stability in plants have increased considerably and this has led to improved methodologies and important mechanistic insights. In this review, we highlight some of the most interesting examples of plant transcripts that are controlled at the level of mRNA decay and discuss what has been learned from their study. Experiments that implicate or demonstrate the involvement of particular cis- and trans-acting factors in mRNA decay pathways are a major focus, as are those experiments that have led to mechanistic models. Emphasis is also placed on studies that address the relationship between translation and mRNA stability. Our current knowledge indicates that some of the determinants and pathways for mRNA decay may differ in plants compared to other eukaryotes, whereas others appear to be similar. This knowledge, coupled with the availability of biochemical, molecular and genetic approaches to elucidate plant mRNA decay mechanisms, should continue to lead to findings of novel and general significance.