Masters ThesisFoot-and-mouth disease (FMD) is a highly contagious disease that infects cloven hoofed animals. FMD is caused by FMD virus (FMDV), a picornavirus with a positive sense single stranded RNA genome of about 8.5 kb in size. FMD is endemic in East African countries including Tanzania. The general objective of this study was to determine the genetic characteristics of recently circulated serotypes O and A FMDV field strains in selected regions of Tanzania in 2019. A total of 36 (four serotype O and 22 serotype A) archived epithelial samples collected from cattle and pig in Kibaha, Morogoro, Sengerema, Butiama and Musoma were used in this study. The laboratory analysis of the samples was performed by reverse transcription polymerase chain reaction (RT-PCR) targeting the 3D and VP1 coding regions, VP1 sequencing and phylogeny. The RT-PCR results revealed that 72% of samples (n= 26) were positive for FMDV genome. Molecular typing of the FMDV genome positive samples was achieved by using serotype specific primers of which serotypes A were 85 % (n= 22) and O were 15 % (n= 4). Phylogenetic reconstructions were determined by neighbour-joining methods. Phylogenetic analysis of VP1 showed genetic diversity among the circulating viruses and their molecular relatedness with previously recorded sequences from East Africa, particularly Kenya and Tanzania. These findings indicate that the 2019 FMDV types A and O responsible for the disease outbreaks in Tanzania were the East Africa 2 (EA-2) and genotype I (GI) which showed a very closely evolutionary relatedness with previous strains collected in Kenya and Tanzania. Further studies are required to design new vaccine strains so as to prevent upcoming outbreaks.