A retrospective study of sera from seven commercial pig herds was conducted from May 1985 to July 1989, showing that antibodies against Porcine Respiratory Coronavirus (PRCV) were first detected in Spain in September 1986. During 1991 a stratified sampling of breeding herds was conducted to establish prevalence to PRCV or Transmissible Gastroenteritis Virus (TGEV) infections in Catalunya (northeast Spain). An antibody-capture ELISA was used for PRCV- and/or TGEV-antibodies, while a competitive inhibition ELISA tested for TGEV-specific antibodies. This study revealed 91.1% positive sera and 96.7% positive farms to PRCV and/or TGEV with a gradual increase in prevalence during 1991, which was more noticeable in small herds. Of the total 569 herds tested, 65.2% were positive only to PRCV, 8.6% were positive to TGEV and 22.8% had mixed infections. The first appearance of antibodies coincided with large importation of feeder pigs from Belgium and Holland. This prevalence is much higher than previously reported in other regions of Spain. © 1994.