This study describes development of a multiplex PCR assay for detection of BHV-1, BVDV, Chlamydia spp. and Mycoplasma spp. infections in bovines. The assay was developed using genomic DNA and RNA and four sets of PCR primers targeting 16S rRNA genes of Chlamydia spp., Mycoplasma spp., 5’-UTR of Bovine viral diarrhea virus, gE of Bovine herpesvirus-1, respectively. A total of 100 tissue samples were collected from cattle suspected to be infected with the viral and bacterial pathogens (BVDV, BHV-1, Chlamydia spp. and Mycoplasma spp.) from different regions of Ukraine. A part of sample was stored at –50°C for isolation of genomic DNA and RNA. The multiplex PCR assay was optimized in the study. The specific primers designed and used in the study were found sensitive and specific in amplifying target genes viz. 16S rRNA, gE, 5’-UTR of Chlamydia spp., Mycoplasma spp., BHV-1 and BVDV, respectively. The PCR primers used in the optimization of multiplex PCR assay for detection of Bovine viral diarrhea virus, Bovine herpesvirus-1, Chlamydia spp., Mycolasma spp. could amplify 221 bp, 111 bp, 386 bp, 279 bp products, respectively. Non specific amplification was not observed