Since their introduction in the early 1990s, pulsating heat pipes (PHPs) have received a lot of attention due to their obvious advantages such as their geometrical simplicity, and their potential for high-heat flux applications even without power consumption. Although numerous investigators have studied PHPs over the last three decades, there still exist a few controversial issues on fundamental characteristics and several technical problems in practical applications. To put the finishing touches to the controversial issues and to shed light on the technical problems, recent advances in PHPs are critically reviewed in this paper. The results of this critical review are classified into two categories: (i) fundamental aspects of PHPs and (ii) practical aspects of PHPs. The first category focuses on reviewing the current state-of-the-art fundamental characteristics of PHPs. The second category summarizes the technical problems that are resolved for utilizing PHPs in practical applications. This review paper would help researchers or engineers who are working on or utilizing PHPs.