Antibody-based drugs are now used in the clinic, and their importance as therapeutics is expected to increase in the coming decade, both in terms of diseases treated and market value. However, the proportion of patients that can be treated is to some extent affected by the availability and cost of the therapeutic. Therefore, the means of production and purification of the therapeutic entity, as well as the type of therapeutic entity, are of great concern. Escherichia coli represents a good production host in terms of scale and speed of production, but it also has technical and biological limitations. The aim of this review is to describe and discuss the relative benefits and limitations of E coli as a host for the production of antibodies and engineered antibody fragments.