He graduated in 1991 at the University of Veterinary Science, Budapest.

He started his carrier at the Agricultural University of Gödöllő.

Since 1994 he works at the Laboratory of Bacteriology of the Central Veterinary Institute’s (its accessor is the National Food Chain Safety Office since 2012).

His Ph.D. Thesis „New data to the pathophysiology, clinics and therapy of bovine mastitis” was defended successfully in 2003.

His research activity covers the bovine mastitis, animal diseases caused by bacteria especially bovine tuberculosis and Johne’s disease and antimicrobial resistance of bacteria, as well. In the above topics he is a regular teacher of university and postgraduate educations and trainings.

Sz. Jánosi is the author or co-author of 51 scientific publication and book chapter whose cumulative impact factor is 30.659.