Introduction: The registration of adverse events after the use of immunological veterinary medicinal products (VMP) is the aim of the vaccinovigilance reporting system in Switzerland. Adverse events comprise suspected adverse reactions and lack of expected efficacy. Since the Institute of virology and immunology (IVI) is the competent authority for the regulation of immunological VMP in Switzerland, the reporting system is administrated by the IVI. In 2018, 162 reports concerning authorized immunological VMP were received. While most of the reports were submitted by the marketing authorization holders (79%), practicing veterinary surgeons contributed to the reporting system, too (18%). Five reports were submitted by private persons (3%). Dogs were mainly affected (43%) with several terrier breeds and chihuahuas being the most frequently reported dog breeds. Further reports were related to cats (16%), cattle (14%) and horses (14%). Recently, the numbers of reports concerning cats (+26) and horses (+23) have considerably increased after there had been clearly less reports concerning these species (11 and 5, respectively) in the previous year. Most of the reports were based on the application of combined vaccines against canine distemper, hepatitis, parvovirosis and parainfluenza with or without leptospirosis in dogs as well as cat flu and feline panleukopenia in cats. In 29.6% of the submitted cases, the causality assessment between the vaccination and the reaction described was evaluated probable.