The study aims to investigate the effect of cooperative learning in promoting reading and writing skills in second year Sudanese EFL students at University of Khartoum. The researchers used quasi experimental and analytical descriptive approaches. The subjects of the study were (43) students representing the second year of English department in the academic year (2017-2018). The treatment was done within two phases. In phase (1) the class divided into two groups; 22 students representing the experimental group and another (21) students as a control group in reading comprehension. In phase (2) the two groups were reversed the control group became experimental and the experimental group became control group in writing skill. Pre and post tests were conducted to both groups in the two phases of the treatment. After the treatment, a random group of (27) students were selected to respond to attitudes questionnaire. The results of the study showed that there was a significant difference between the students who taught with cooperative learning and those who were being taught by the traditional whole class- method in both reading and writing skills. Additionally, the high achiever students (high GPA), gain most from cooperative learning in writing skill and more importantly, the majority of second year students have positive attitudes towards cooperative learning. Based on these results, several theoretical and pedagogical implications are provided