[en] The Nuclear Regulatory Authority (ARN) carries out the monitoring of the environment surrounding Argentina nuclear power plants, independently from the operators' own monitoring programmes. Recently, there has been a review of the criteria used for selecting target radionuclides, sampling matrix, sampling location, and sampling frequency. This revision was based on ARN objectives for an environmental radiological monitoring programme, which are: verification of discharge monitoring results and detection of unadverted/unauthorized emissions; verification of models assumptions and checking that doses to the critical groups are not exceeded; detection of radionuclides presence in the environment and trend analysis; and to provide information to the public. The criteria proposed for adoption implies the monitoring of the relevant radionuclides mentioned in the discharge authorization license, using specific analysis for those considered indicators and screening techniques for the others. The matrix to be sampled must be related with the different exposure pathways, from those related with direct exposure, which require higher sampling frequencies, to accumulating/concentrating matrices, which imply lower sampling frequencies. At least, three points should be sampled, related to both airborne and liquid emissions: a background location, the representative person location, and that where the concentration of a target radionuclide is expected to be maximum. Available modeling software was used for positioning the sampling points. (author)