Geranium has an important place in the world flower and plant industry and is one of the most popular for indoor and outdoor use. Viral diseases play an important role in reducing the quantity and quality of this ornamental plant. In this study, 72 samples suspected of viral infection with symptoms such as bright ring spots, leaf necrosis and chlorosis, spots or color breaking on the petals, as well as asymptomatic plants were collected from various greenhouses in the Mahallat and Varamin and their suburbs. Total RNA was extracted and evaluated by RT-PCR using general primers of the family Tombusviridae. In 21 samples, a DNA fragment of 500 base pair (bp) in size was amplified using Tombusviridae primers. This DNA fragment from the two isolates were sequenced and compared with the sequences available in the Genbank database. The results indicated that both isolates belonged to Pelargonium flower break virus (PFBV). The RT-PCR test was performed again using a pair of specific primers (CH1/GH2) designed to amplify a 1500 bp DNA fragment from the 3' end of the PFBV virus genome containing the coat protein gene on the same samples, that confirmed the accuracy of the results of the previous step. The amplified DNA formed on the gel of three selected isolates was extracted from the gel and subjected to sequencing. Phylogenetic analysis was performed based on the amino acid sequence of CP gene and phylogenetic tree (genealogy) was drawn using neighbor joining method. The results of phylogenetic analysis showed that the reported PFBV isolates from different countries are in two groups and three PFBV isolates of Iran were placed separately in one subgroup from the subgroups of other countries. This is the first report of PFBV in Iran.