Surface active agents can be classified 60 years ago with the introduction of the HLB system. The characterization of emulgents allowed their common use in the practice. The objective of the review is to summarize the research in the field of surface active agents and HLB-value. The basic principles and relationships related to HLB are detailed such as the predicting and experimental methods for the determination, as well as the achievements of development and applications of surface active agents.