The last decade led to the discovery and characterization of several human β-defensins. Analysis of genomic information indicates that the number of β-defensin-like molecules encoded by the human genome may number in the tens. Growing interest in β-defensins steadily enhances our knowledge about various aspects of their gene location, expression patterns and the transcription factors involved in their regulation in vivo. The hallmark property of β-defensins, their antimicrobial activity, is clearly only the tip of the iceberg in the extensive network of inter-relations within the immune system in which these peptides function. Structural studies of β-defensins provide the molecular basis for a better understanding of their properties, functions and their potential for practical applications. In this review, we present some recent advances in the studies of human β-defensins, with an emphasis on possible correlations between their structural and functional properties.