Plasma cell dyscrasias are a group of related disorders that have in common the clonal proliferation of plasma cells with resultant production of a monoclonal immunoglobulin that can be detected on serum protein electrophoresis (M-spike). This term incorporates the Plasma Cell Neoplasms along with other related disorders that are not considered malignant. Comprehensive genomic studies have greatly advanced our understanding of the genetic complexity of these diseases in recent years, however they continue to be considered incurable with a highly heterogeneous phenotype. It is clear that a deeper level of knowledge of the biological events underlying the development of these diseases is needed to identify new targets and generate effective novel therapies. MicroRNAs (miRNAs), which are single strand, 20- nucleotide, non-coding RNAs, are key regulators of gene expression and have been reported to exert transcriptional control in multiple myeloma and other plasma cell dyscrasias. miRNAs are now recognized to play a role in many key areas such as cellular proliferation, differentiation, apoptosis and stress response. Substantial advances have been made in recent years in terms of our understanding of the biological role of miRNAs in this complex and diverse set of disorders, leading to the new information, which is of diagnostic and prognostic relevance.