The myxobacteria are an order of abundant and virtually ubiquitous soil-dwelling Deltaproteobacteria. They initially attracted scientific attention in the nineteenth century for their ability to aggregate when starved, cooperating as a population of cells to form multicellular fruiting bodies containing differentiated cell types. Later, it became apparent that myxobacteria were also predatory organisms, able to kill and consume a broad range of microbes, including both bacteria (Gram-positive and Gram-negative) and fungi. Myxobacteria are copious producers of secondary metabolites, many of which are being exploited industrially as antibiotics and cytotoxic compounds, and such metabolites are presumed to be causally involved in myxobacterial predation in the environment. Predation by the myxobacteria has continued to receive less interest than either their multicellular development, or their secondary metabolite production. Nevertheless, research is beginning to provide an understanding of several fundamental aspects of myxobacterial predation, particularly for the model predatory myxobacterium Myxococcus xanthus. New insights have been mainly mechanistic, focussing on how myxobacteria kill prey, but are also increasingly ecological. We are starting to understand environmental factors that affect predatory activity, the distribution and diversity of predator and prey species in various ecosystems, and how interactions between predator and prey cells affect predatory success.