This article highlights the most common morphologic features identified in the bone marrow after chemotherapy for hematologic malignancies, growth-stimulating agents, and specific targeted therapies. The key is to be aware of these changes while reviewing post-therapeutic bone marrow biopsies and to not mistake reactive patterns for neoplastic processes. In addition, given the development and prevalent use of targeted therapy, such as tyrosine kinase inhibitors and immune modulators, knowledge of drug-specific morphologic changes is required for proper bone marrow interpretation and diagnosis.