The article presents a global transcriptional analysis of Mycoplasma hyopneumoniae, a causative agent of swine enzootic pneumonia which colonizes the swine lungs' cilia, resulting to cell death and ciliostasis. It is a component of the porcine repiratory disease complex (PRDC) and is significantly problematic in the swine industry, resulting to a deficit of hundreds of millions of dollars in revenues of farms worldwide. For a successful infection, this causative agent must be able to resist oxidative stresses triggered by the release of oxidative compounds originating from macrophages and neutrophils during the host's immune response.