The human obese subcutaneous adipose tissue (SAT) contributes to systemic and B cell intrinsic inflammation, reduced B cell responses, and increased secretion of autoimmune antibodies. Immune cells are recruited to the SAT by chemokines released by both adipocytes and infiltrating immune cells. We describe here the characterization of B lymphocytes from the SAT and blood (control) of obese females undergoing weight reduction surgeries (breast reduction or panniculectomy). We show how to isolate the immune cells from the blood and SAT, how to characterize B cells and their subsets, and how to measure markers of activation and/or transcription factors in SAT-derived B cells and B cell subsets. We also show how to evaluate other immune cell types infiltrating the SAT, including T cells, NK cells, monocyte/macrophages, in order to measure relative proportions of these cell types as compared to the blood.