The differences in cognitive style between individuals and the effect these differences can have on second language learning have long been recognized by educators and researchers. Hence, this issue is the focal center of the present study. More precisely, the purpose of this study was to investigate the role of participants' cognitive style (field dependence vs. field independence) in their collocational knowledge development. That is, the study explored possible differences between field-dependent and field-independent learners with regard to the role of input flood treatment as an implicit method of collocation instruction. Two intact classes comprising sixty-four upper-intermediate learners with roughly the same level of language proficiency participated in this study. One class was randomly assigned to the experimental group and the other to the control group. The analysis of the data revealed that input flood treatment improved the performance of the experimental group at post-test stage. A deeper analysis concerning the differences between field-dependent/independent learners, however, indicated that this kind of teaching approach was more beneficial for field-independent learners in both short and long term. Moreover, the results of within-field-dependent/independent group showed that while input flood treatment did not have long-term effect on improving the field-dependent's knowledge of the target collocations, it had durable effect on the field-independent's collocation development.