Evaluation of the central nervous system (CNS) in the developing mouse presents unique challenges given the complexity of ontogenesis, marked structural reorganization over very short distances in three dimensions each hour, and numerous developmental events susceptible to genetic and environmental influences. Developmental defects affecting the brain and spinal cord arise frequently both in utero and perinatally as spontaneous events, following teratogen exposure, and as sequelae to induced mutations, and thus are a common factor in embryonic and perinatal lethality in many mouse models. Knowledge of normal organ and cellular architecture and differentiation throughout the mouse’s lifespan is crucial to identify and characterize neurodevelopmental lesions. By providing a well-illustrated overview summarizing major events of normal in utero and perinatal mouse CNS development with examples of common developmental abnormalities, this annotated, color atlas can be used to identify normal structure and histology when phenotyping genetically engineered mice (GEM) and will enhance efforts to describe and interpret brain and spinal cord malformations as causes of mouse embryonic and perinatal lethal phenotypes. The schematics and images in this atlas illustrate major developmental events during gestation from embryonic day (E) 7.5 to E18.5 and after birth from postnatal day (P)1 to P21.