OncomiRs are microRNAs which are known to be deregulated in various cancers. Since they are highly conserved between the genomes of related species and show a characteristic evolutionary divergence, they provide an ideal platform for computational analysis. This would augment the experimental procedure to identify and validate the role of microRNAs that are involved in the deregulation of key targets and pathways leading to the development of breast cancer. With this as the aim, we started mining miRNAs and their targets involved in different pathways, such as the wnt, Jak- Stat, MAPK, mTOR, VEGF, Apoptosis and Notch that are deregulated in breast cancer, using different online softwares and databases. Here we present oncomiRdbB, a comprehensive and integrated database of miRNAs, targets, their hubs and networks of various pathways which are involved in Breast cancer initiation, progression and metastasis.