Dahlia common mosaic virus (DCMV) was reported for the first time in Kurdistan Region of Iraq that is associated with dahlia (Dahlia pinnata) mosaic diseases. The virus was described as an unclassified Caulimovirus. In such manner, 50 symptomatic dahlia plants showing viral symptoms were collected in 2020–2021 from various nurseries and local gardens located in Duhok city of Kurdistan Region of Iraq. The collected samples were tested for the incidence of caulimoviruses related to dahlia mosaic diseases including dahlia mosaic virus (DMV), DCMV, and DMV-D10, using PCR. The presence of two distinct caulimoviruses, DMV and DCMV, and the absence of DMV-D10 were confirmed by amplification of the used specific primers. Mixed infections were common in the tested samples. The amplified fragments were cloned, sequenced, and compared with those available in GenBank. There is little information on the biological properties of DCMV. This study highlights some of these properties including host range and symptomology of the virus in mechanical transmission and the role of three aphid species in the virus transmission. To our knowledge, this is the first detailed study on the biological properties of DCMV.