This study investigates the efficacy of explicit rhythm instruction to improve engineering students' prosody in English. A pronunciation module of ten weekly sessions of 30 minutes held within the class schedule was designed for a technical English course at Rovira i Virgili University. Sessions were outlined using a communicative framework. Two hundred and ninety eight Spanish/Catalan students were divided into three experimental groups receiving rhythm instruction, and three control groups which did not. Students were recorded before and after the training. Six native American English speakers were also recorded as a reference point. VarcoV values were measured and compared using PRAAT and the data were analysed using mixed analysis of variances (ANOVAS) and t-tests. Results reveal that the experimental group tends to increase in VarcoV after training, approaching English rhythm, while the control group presents incongruences. Despite results not always being significant, an analysis of the effect sizes for the t-tests comparing before and after VarcoV values for the experimental vs. the control groups shows significance. These results support the hypothesis that rhythm instruction can be beneficial to improve English for Specific Purposes (ESP) students' prosody. [For the complete volume, "ESP Teaching and Teacher Education: Current Theories and Practices," see ED595614.]