MicroRNA (miRNA) have been recently attributed a crucial role in the control of gene expression in numerous physiological and pathological processes including growth, differentiation and even oncogenesis. Besides detailed mechanistic studies on their generation and function, there has been a great deal of interest in the study of miRNA as surrogate markers of disease. Numerous studies have attempted to define miRNA profiles as predictors of disease outcome, or for the classification/diagnosis of different pathologies. In the present review, we summarize the main studies describing the involvement of miRNA in bone marrow (BM) diseases and in normal BM function during hematopoiesis.