In this paper we target Natural Language Understanding in the context of Conversational Agents that answer questions about their topics of expertise, and have in their knowledge base question/answer pairs, limiting the understanding problem to the task of finding the question in the knowledge base that will trigger the most appropriate answer to a given (new) question. We implement such an agent and different state of the art techniques are tested, covering several paradigms, and moving from lab experiments to tests with real users. First, we test the implemented techniques in a corpus built by the agent’s developers, corresponding to the expected questions; then we test the same techniques in a corpus representing interactions between the agent and real users. Interestingly, results show that the best “lab” techniques are not necessarily the best for real scenarios, even if only in-domain questions are considered.