Vesicular trafficking is the major style for cargo transport and cell signaling in eukaryotic cells, in which Rabs play very important roles. Rab4 is one member of the Rab protein family involved in regulating early endosomal sorting and recycling pathway. Based on the different structure characteristics, Rab4 can be classified into three isoforms, including Rab4A, Rab4B and Rab4C. In this review, Rab4’s biological characteristics such as their structure, effectors and cargo proteins, were summarized and its role in autophagy, glucose uptake, neuromodulation, cardiac function and tumorigenesis was discussed.