The successful propagation of many viruses within their hosts requires the evasion or manipulation of the host's defenses. Poxviridae family comprises large DNA viruses capable of infecting vertebrate and invertebrate hosts, causing introduced and naturally occurring infections in all populated continents, including Brazil. The vaccinia virus (VV), the prototype member of poxviruses, replicates entirely in the cytoplasm of infected cells and its double-stranded DNA encodes more than 260 gene products, many of them are associated with virus-host interactions. We have previously shown that VV manipulate the mitogen-activated protein kinases (MAPKs). The recruitment of MAPK pathway, MEK/ERK 1/2, is biologically relevant since its disruption caused a profound effect on VV multiplication (Andrade et al, 2004). MAPKs play a critical role in the transduction of wide variety of extracellular signals. This pathway include the extracellular signal-related kinases (ERKs), which are activated by growth factors and many other mitogenic stimuli and c-Jun-terminal kinases (JNK/SAPK I) and p38 MAPKs (SAPK II), which are activated by stress stimuli leading to growth arrest and apoptotic responses. In this study, we demonstrated that cowpox virus (CPV), the etiologic agent causative of localized and painful vesicular lesion in cattle, zoo animals and zoonotic in Europe and Asia, and Araçatuba virus (ARAV), isolated from outbreak in Brazil, both from genus Orthopoxvirus and related to VV, also trigger the activation of MAPKs pathway. Experiments were carried out after depriving A31 fibroblasts cells with 1% of fetal bovine serum for 12 hours and then virus-infected at multiplicity of infection of 5. CPV infection, triggers the phosphorylation of the transcription factor ATF-2 from 2-10 hours post-infection (hpi) apparently via JNK, while p38, its other upstream activator, was activated only after 24-48 hpi. Although p38 is activated at later stages of CPV multiplication, the inhibition of this pathway does not seem to be biologically relevant. We have also observed an increasing in AP-1 DNA-binding activity from 1 to 48 hpi. Similarly, ARAV infection also activates ERK, from 1 to 48 hpi., while JNK is activated at later times, (6-60 hpi). Preliminary results suggest that JNK seems to be the most relevant pathway activated during ARAV infection as also observed with CPV infection.