Mice are a significant model organism for studying mammalian development. The information obtained from mice helps us understand humans. However, there are significant differences in the biological mechanisms between mice and humans. Non-human primates serve to bridge the gap between these species. Primate biological mechanisms are largely unexplored, although understanding the mechanisms is essential for advancing human biology, which contributes to improving medicine and increasing our wisdom. Marmosets are an attractive model for studying primate development. They are small and relatively easy to handle. Developmental mechanisms are mostly shared between marmosets and humans, although initial developmental speed is somewhat delayed in marmosets. Furthermore, good foundations for studying biological and medical science (e.g., development, reproductive science, neuroscience, behavioral science, regenerative medicine, pharmacological science, and the development of new treatments) have been established in marmosets. Detailed fundamental methods, on the other hand, are frequently unavailable. This Methods Collection intends to help researchers get started with marmoset experiments. It will include a variety of fundamental techniques for experiments, such as the generation of genetically modified marmosets and husbandry (i.e., care, breeding, and artificial nursing). In addition, the collection will also include techniques for using marmosets as model organisms in biomedical research. Techniques linked to reproductive biology, stem cell biology, molecular biology, immunology, neuroscience, aging, behavioral science, toxicology, and other fields will be covered.