Objectives: The aim of this study was to identify viral proteins of mouse cytomegalovirus (MCMV) prone to liquid-liquid phase separation (LLPS) and to investigate whether the replication compartments and the cytoplasmic virion assembly compartment (cVAC) are organized as biomolecular condensates, i.e. whether the process of LLPS is the mechanism of organizing accumulated viral proteins in these compartments. Material and Methods: Using bioinformatics tools, we examined the LLPS propensity of 168 MCMV proteins. Using the immunofluorescence and confocal microscopy in Balb 3T3 infected cells, we performed detailed spatial and temporal characterization of MCMV proteins E1 (M112-113), M57, M25 and m48.2 (SCP) during the early and late stages of infection and then tested their sensitivity to 1,6-hexanediol (1,6-HD) and propylene glycol (PG). The expression of proteins E1 (M112-113), M57 and M25 in untreated cells was also monitored by Western blot analysis. Results: Out of a total of 58 MCMV-encoded proteins, LLPS propensity was detected by bioinformatics tools in tegument proteins M25, M32, M45 and M69, capsid protein m48.2 and proteins M44, M57, m18 and M80. Only five MCMV proteins (E1, IE3, M25.3, M34 and M58) out of a total of 110 analyzed noncoding MCMV proteins, have a high propensity for LLPS. Proteins E1, M57, M25 and m48.2 form membraneless assemblies in the nucleus of infected cells, and p (protein) M25 also in the area of cVAC. Treatment with 1,6-HD and PG dissolved pE1 membraneless assemblies in the early, but not in the late phase of infection. Cytoplasmic pM25 membraneless assemblies in the area of cVAC are partially sensitive to 1,6-HD and PG, and nuclear forms are resistant both in the early and late stages of infection. Membraneless assemblies of pM57 and pm48.2 are not sensitive to 1,6-HD and PG in the late phase of infection. The sequence of nuclear and cytoplasmic events that is required for efficient virion production fails to be completed in all infected cells. Conclusion: Compartmentalization by the formation of nuclear and cytoplasmic membraneless compartments in infected cells can be achieved by mechanisms involving LLPS. Only a relatively small proportion of infected cells manages to provide all the necessary steps for the formation of mature virions, which indicates that the compartmentalization of events in the infected cell, that is, their spatiotemporal organization is not efficient in all cells.