Beige and brown adipocytes are thermogenic cells essential for maintaining metabolic homeostasis within white adipose tissue (WAT) and brown adipose tissue (BAT), respectively. Emerging studies indicate that various immune cell types such as alternatively activated macrophages (AAMacs), eosinophils, and group 2 innate lymphoid cells (ILC2s) critically regulate beige and/or brown adipocyte development and activation to protect against obesity and maintain core body temperature. These findings suggest that studies of beige and brown adipose tissue may benefit from traditional immunologic approaches such as flow cytometry of immune cells residing within WAT and BAT. The purpose of this article is to describe an efficient method to isolate immune cells from numerous adipose tissue samples in parallel. The composition, phenotype, and activation state of cells isolated with this protocol may then be assessed by multiple methods including but not limited to flow cytometry. As an example, this article briefly describes a method to identify AAMacs, eosinophils, and ILC2s in adipose tissues.