<p>Recycling is one of the important goals of municipal solid waste management that significantly depends on the cooperation of citizens in source separation. The perceived benefits in economic and environmental aspects of recycling can be an effective factor in increasing source separation. In this cross-sectional study, perceived environmental and economic benefits in 1436 citizens in Iran were surveyed using a questionnaire. For this purpose, the cost-benefit of the current situation and the defined scenarios based on increasing the source separation ratio were estimated using Monte Carlo simulation in a thousand replicates and log-normal distribution data. The results showed that 63.64–88.36% of the respondents understood the environmental benefits of recycling and 62.32–90.1% understood the economic benefits of recycling. However, 1282 people (89.27%) did not or rarely separate recyclable waste. The results showed that the cost was 18,900 USD/year more than the annual income in current situation, while in optimum scenario the annual income was 842,000 USD more than the cost. The inconsistency of citizens’ behavior with perceived benefits indicates the need to consider the hypothesized mediators between the perceived benefits and citizens’ behavior regarding source separation of recyclable wastes and external factors such as local laws to increase the ratio of source separation. Also, the economic benefits (increasing recycling revenues and reducing landfill costs) resulting from increased source separation can be considered as an advantage by decision maker to implement optimal scenarios.</p>