A connection system for an electrosurgical instrument comprises first and second connectors capable of being mated one with the other, the first connector (5) being associated with an electrosurgical generator (1) and the second connector (12) being associated with the electrosurgical instrument (9). The first and second connectors each include at least three connector components, each of the three connector components of the first connector (5) being capable of being connected and disconnected to a to respective one of the three connector components of the second connector (12). When the first connector components (14, 19) are connected to each other they are capable of delivering an RF energy output from the electrosurgical generator (1) to the electrosurgical instrument (9). When the second connector components (16, 22) are connected to each other they are capable of delivering a supply of ionizable gas to the electrosurgical instrument (9). When the third connector components (15, 21) are connected to each other they capable of identifying the electrosurgical instrument (9) to the electrosurgical generator (1). When the first and second connectors are mated one with the other, the third connector components (15, 21) are connected one to the other only after the first and second connector components are connected one to the other.
