Choice experiments have become an important tool to provide guidance about the value of environmental goods and services. Several evidences, however, are pointing toward an important mismatch between the rationality principles assumed by this methodology and real respondents’ behaviour, what may be giving rise to inconsistent choices. This paper studies the effects of such inconsistencies by using data from an online survey aimed at valuing the environmental impacts of organic farming in mountainous olive groves. The results are analysed by means of three random parameter models and provide evidence on the necessity to appropriately consider and treat choice inconsistencies as a result of their influence on welfare estimates.