Differential abundance and activity of long noncoding RNAs (lncRNAs) are recognized as the hallmark features in various diseases. We highlight the lncRNAs that play a functional role in the development of blood cells. Many lncRNAs and the protein complexes within which they interact have been implicated in various types of cancers. Multiple lncRNAs participate in normal and may be implicated in malignant hematopoiesis associated with blood cell cancers, such as leukemia, by regulating gene expression through such mechanisms as redirecting chromatin remodeling complexes and activating epigenetic silencing, either of which can inactivate tumor suppressor genes or activate oncogenes. Because of their potential importance in cancers of the blood, lncRNAs may be useful as diagnostic and prognostic markers, and it may be possible to develop lncRNA-mediated therapy.