The article starts by a brief presentation of concepts surrounding the assessment of an environmental impact, as well as the methods more frequently used and mentioned in the literature. A distinction between methodology, methods and techniques is also presented, followed by a concise examination of the pros and cons of the different methods and techniques, stressing the limits which prevail in their application. Based on a consideration of said aspects and also taking into account some Brazilian and foreign studies, an appraisal is centered in the way which occurs the usage of such methods in the assessment of the environmental impact, in the area of enterprises of the electric sector. There is also mention of some works developed by the sector and which represent a methodological progress, being valid, at the same time, as subsidies for future studies.Conceituação da avaliação de impacto ambiental. Métodos mais utilizados e citados na literatura. Distinção entre metodologia, métodos e técnicas. Vantagens e desvantagens dos diversos métodos e técnicas. Avaliação da aplicação desses métodos no âmbito dos empreendimentos do setor elétrico.