The invention relates to a drop-in cell for disinfection of water from bathing pools, particularly whirlpools, with an electrolytic cell (10) which can be flowed through by water and has two contact electrodes (1, 2), which are positioned in parallel and spaced apart from each other, and preferably at least one bipolar diamond particle electrode (3), which is arranged between the contact electrodes (1, 2) at a distance from them.The electrodes (1, 2, 3) are joined together by spacers (4) located between them to form an elongate, approximately cuboidal electrode pack, which is embedded in a casing (6) of plastic or synthetic resin while leaving an inflow and an outflow free. The user/customer is therefore provided with a drop-in cell which can be positioned in the circuit of the pool water or in the whirlpool and can be “installed” or, as and when required, removed and/or replaced without any problem by the user/customer himself.