Peripheral blood is often used for in vitro studies of the human immune system or immune responses, such as inflammation. An important part of the human immune system is represented by the peripheral blood mononuclear cells (PBMC). PBMC are blood cells characterized by a round nucleus and consist mainly of lymphocytes (T cells, B cells, and NK cells), macrophages and dendritic cells. Here, we describe the analysis of lipopolysaccharide-induced transcriptional response of isolated PBMC from whole blood using the RNeasy® Mini Kit or RNeasy Micro Kit, RT2 First Strand Kit, RT2 SYBR® Green ROX™ qPCR Mastermix, and RT2 Profiler PCR Arrays.