To understand better a complex disease such as psoriatic arthritis (PsA), collection of a large amount of information on clinical, laboratory, and radiological features is required over an extended period of time. Longitudinal data can be effectively collected and stored in clinical registries and databases. This article reviews current databases in PsA and proposes a structure for an international PsA registry. Careful collection and analysis of patient data through collaborative efforts will likely advance our knowledge of pathogenesis and provide new and much needed insights about the course and prognosis of the disease.