This research study explored the impact of learning styles and input modalities on the second language (L2) learners' input processing (IP). This study also sought to appraise the usefulness of Processing Instruction (PI) and its components in relation to the learners' learning styles and input modalities. To this end, 73 male and female Iranian EFL learners from Islamic Azad University, North Tehran Branch participated in the study. The participants from four intact classes were exposed to PI. The data were collected through a pre- test and two parallel posttests on the target structure, reconstructive elicited imitation tasks in both aural and written modes, and a structured interview. The data were analyzed using MANOVA. The findings revealed that the ectenic learners had a more form-based rather than a meaning-based approach towards IP. Input modality was also revealed to be an influential factor in L2 learners' IP. Furthermore, the Explicit Infor- mation (EI) turned out to be more of use to the ectenic learners while the synoptic group largely benefited from the Structured Input (SI) activities. پرونده مقاله