Aims & objectives: The purpose of this study was to evaluate the impact of the beliefs of obligation of taking care of the resources and the attitudes towards three kinds of pro-environmental behavior. Context & Background literature: The environmental problems which cities confront are diverse and require solutions in which the population actively participates. To recognise the factors that lead such participation has turned into a main goal. The research of the determiners of the pro-environmental behavior has started from several predictors and diverse theorical models. Beliefs have been associated with water conservation (Corral-Verdugo, Bechtel, & Fraijo-Sing, 2003), attitudes with ecological behavioral intention (Kaiser, Ranney, Hartig & Bowler, 1999) and with water conservation (Martimportugués, Canto, García & Hidalgo, 2002). According to these studies, a united evaluation of beliefs and attitudes represent a possibility of important inquiry. Method: The sample involved 300 inhabitants of México City with an average of 32 years of edge (range = 18-73), an average of 12 years of schooling, and an average monthly income of $5478 Mexican pesos. Half the subjects were female and the other half, male, who were interviewed at their own residence. The instruments used were Likert scales in order to measure the beliefs about taking care of the use of electric power, recycling, water conservation, and beliefs of obligation. A scale of semantic differential was constructed to evaluate attitude. Findings and conclusion: In terms of average values, 2.89 was the result for recycling, 2.88 for taking care of electric power, and 3.52 for water conservation, being the minimum scale value 1 and the maximum 4. By regression analysis it was found that the consumption of electric power, recycling and water conservation were predicted mainly by the beliefs of the obligation of taking care of the resources and the specific attitude of each behavior. It was concluded that the beliefs of obligation represent an important predictator of environmental action and that, when set together, along with the attitude, form a more appropriate predictive model. Finally, we discussed the relevance of the results for an environmental education campaign.