Abstract: If the presence of residual solvents in pharmaceuticals exceeds tolerance limits as suggested by safety data, they may be harmful to the human body or the environment. It is because of this that the determination of residual solvents receives a great deal of attention. This paper reviews in detail the changes in the regulations on residual solvents in pharmaceuticals in leading pharmacopoeias, and the advances in the techniques involved, especially, the recent advances in the analytical techniques are summarized. At the end, the authors introduce the prospect of the expert system for determining residual solvents in pharmaceuticals based on the studies of their research group.