Abstract Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the coccidiostat lasalocid A sodium (Avatec® 150G) for chickens for fattening and chickens reared for laying. Taking into account the results of all tolerance studies submitted for the re‐evaluation of the additive, the FEEDAP Panel considers that lasalocid A sodium from Avatec® 150G is safe at a maximum content of 90 mg/kg complete feed for chickens for fattening. A margin of safety cannot be established. No conclusion on the safety of lasalocid for chickens reared for laying can be made. Three new floor pen studies showed efficacy of 90 mg lasalocid A sodium/kg complete feed reducing the adverse clinical consequences of an Eimeria infection in chickens for fattening. Considering also the previously reported positive floor pen study and the three positive anticoccidial sensitivity tests, the FEEDAP Panel can conclude on an efficient coccidiostatic level of 90 mg lasalocid A sodium/kg complete feed for chickens for fattening. This conclusion is extended to chickens reared for laying.