Abstract: Seroprevalence studies of equine influenza virus in Mexico are very limited. For this reason, the main objective of this study is to start taking a series of samples looking for specific antibodies for equine influenza virus AH3N8 and the pandemic AH1N1 influenza virus. The higher seroprevalence of influenza A H3N8 Equine/Kentucky/CA09 was mainly associated with the dry season (MH-OR = 1.91; p<0.0001), completely farmed horses (MH-OR = 1.554; p<0.0001) with the permanent presence of dogs in the stables (MH-OR = 1.327; p<0.0001), males and sgeldings (MH-OR = 1.239 and 2.136, respectively p<0.0001) of undefined breed and quarter horse cross breed (MH-OR = 1.367 and 1.565, respectively p<0.0001) which were used for ridding and jumping (MH-OR = 1.274 and 1.244, respectively p<0.0001).