Abstract The purpose of this study was to investigate the effect of using task-based learning on developing communication skills in English for the first year university students The researcher employed a sample of (100) EFL learners studying at a university in the Eastern Province in Saudi Arabia. The researcher chose two classes: one class was as an experimental group consisting of (50) students and the second one was as a control group consisting of (50) students. The traditional method was used in teaching the control group, while the task-based learning approach was used with the experimental one in the first term of the academic year (2019-2020). The researcher used three tools: an interview to find out the level of the students in communication skills, a test (pre & post-test), and an observation card to measure the communication skills of the students. The collected data were analyzed and treated statistically. T-test and the effect size equation were used to measure the effect size of task-based learning approach on the experimental group in each domain of the test.