A handheld electrosurgical instrument includes a handpiece (2) and an electrode assembly (3), the electrode assembly including one or more electrodes (12), (13) and a connector (8), (9) by which the electrode assembly (3) is capable of being attached and detached with respect to the handpiece (2). The handpiece includes a battery (4), an RF oscillator circuit (5) for generating a radio frequency output, and switching means (7) operable by a user of the electrosurgical instrument. A control circuit is provided (6) for controlling the RF output, the control circuit (6) being capable of receiving signals from the switching means (7) and causing one or more RF outputs to be supplied to the electrode assembly (3) in response thereto. The electrode assembly (3) includes a component (14), (21) capable of modifying the RF output reaching the one or more electrodes (12), (13) to produce a desired RF output at the one or more electrodes.
