Background <p>Thoracentesis yields valuable insights in pleural effusion diagnosis by accurately interpreting pleural fluid analysis results and can cause several complications, which emphasizes the importance of training in a simulated environment. There are many expensive simulators related to this procedure and few validated scenarios. This study aimed to build and validate a low-cost simulator and a clinical simulation scenario for teaching the thoracentesis procedural technique to undergraduate medical students.</p> Methods <p>This is a methodological study carried out at a public university in the interior of the state of São Paulo, Brazil. It was carried out in three methodological stages, namely: 1) Construction of the simulator, which involved planning, surveying, pricing, and use of material resources 2) Construction of a simulated thoracentesis scenario, based on literature and a simulation script and 3) Validation by experts and pilot study of the simulator and scenario. Experts were selected according to Fehring criteria.</p> Results <p>The simulator proved to be suitable and low-cost (US $18). Modifications to the scenario were suggested by the experts and students in the pilot study, with 100.0% agreement.</p> Conclusions <p>In conclusion, a low-tech, handmade, and low-cost simulator was built and evaluated for training in the thoracentesis procedural technique, as well as a clinical simulation scenario for the management of patients with pleural effusion, which can be included in various medical teaching contexts.</p>