A begomovirus disease complex associated with Sonchus arvensis, a common weed in Pakistan was studied using cloning, nucleic acid sequencing and phylogenetic analysis. The complex associated with this weed consists of a monopartite begomovirus and several distinct betasatellites and alphasatellites. The monopartite begomovirus associated with yellow vein disease of Sonchus arvensis showed 95-99% nucleotide sequence identity with Alternanthera yellow vein virus (AlYVV) reported from China, Vietnam and India. Two betasatellites were isolated from S. arvensis: one sharing between 91.4 and 95.3% nucleotide sequence identity with isolates of Ageratum yellow leaf curl betasatellite (AYLCB), and the other sharing between 78.2 and 99.9% identity with isolates of Cotton leaf curl Multan betasatellite (CLCuMB). Two alphasatellites were identified: one was homologous to Potato leaf curl alphasatellite (PotLCuA), while the other was closely related to Hibiscus leaf curl alphasatellite (HLCuA). Thus, AlYVV in S. arvensis is associated with satellites shown previously to be associated with other begomoviruses in Pakistan. Our results suggest that monopartite begomoviruses may associate with distinct satellites that are prevalent in the region.