Alpha-enolase, also called non-neuronal enolase, belongs to a family of cytoplasmic and glycolytic enzymes. In addition to its glycolytic function, alpha-enolase exerts many other functions in eukaryotes and prokaryotes. Antibodies (Abs) against alpha-enolase have been detected in a large variety of infectious and autoimmune diseases. These Abs might arise as a consequence of a microbial infection or uncontrolled growth or proliferation of cells in specific organs in pathophysiological conditions. In infections, anti-alpha-enolase Abs could play a role in limiting microbial tissue invasion. In autoimmune and inflammatory diseases, anti-alpha-enolase Abs could induce endothelial injury through the generation of immune complexes and activation of the complement classical pathway, inhibit the binding of plasminogen to alpha-enolase with perturbations of the intravascular and pericellular fibrinolytic system, and induce cell death through an apoptotic process. However, further studies are needed to improve our knowledge on the pathogenic role of these Abs.