Considerable progress has been made during the last years in understanding the molecular basis of protein function in pseudorabies virus (PrV), the causative agent of Aujeszky's disease (AD). Major topics have been the identification and functional characterisation of viral envelope glycoproteins and cellular virus receptors, elucidation of viral proteins involved in neurovirulence and neuropathogenesis, detection and characterisation of attenuating mutations present in and leading to successful attenuated live vaccines, and the near completion of the genomic sequence of PrV DNA. This review, which follows an article prepared for the 1993 AD symposium in Budapest, Hungary, will briefly summarise those recent developments and update the reader on the current state of the art in PrV research.