The efficiency of a method which uses A1 (OH)3 for concentrating enterovirus in sewage water was tested in an experimental study. Gel of aluminium hidroxide (in a proportion of 1g per 3,78 1) was added to the previously clarified sewage water with the pH adjusted to 5,0. After shaking for 1 hour, the mixture was filtered through a Millipore membrane type AP-20. The A1 (OH)3 with the adsorbed virus retained on the membrane was removed by means of a spatula. Eagles's medium with 10% foetal calf serum was used for elution and the pH was adjusted to about 7,2-7,4. The mixture was then centrifuged at 20.000 x g, the pellet discarded and the supernatant was inoculated into cells of the strain LLC-MK2 for viral quantification. In a parallel experiment, samples of crude sewage, that is, without previous concentration treatment, were inoculated into cells. This method was shown to be efficient for concentrating enterovirus in sewage water, allowing its detection in samples containing about 1 infectious unit per m1. Without a previous concentration, the isolation of virus from such diluted samples was not possible.