the impact of comprehensible input and This study aimed at investigating Iranian learners oral comprehensible output on the accuracy and complexity of and control groups. The production. The participants were randomly divided into input, output, phase, the input group study involved a pre-task, and a main-task phase. During the pre-task to be engaged i received comprehensible input and the output group was pushed monologues comprehensible output production. In the main-task phase, all subjects performed and that were separately recorded, and later transcribed and coded in terms of accuracy complexity, and finally scored. The results revealed that while both comprehensible input and output improved speech accuracy and complexity, neither was more significant than the other one in this regard.