Impaired processing of working memory information is one of the cognitive deficits seen in patients with schizophrenia. This study aims at corroborating the differences in the brain activities involved in the process of working memory between patients with schizophrenia and the controls. Twelve patients with schizophrenia and 11 controls participated in the study. Functional magnetic resonance imaging (fMRI) was used to assess cortical activities during the performance of a two-back verbal working memory paradigm using the Korean alphabet as mnemonic content. Group analysis revealed that inferior fontal, middle frontal, and superior temporal region showed decreased cortical activities in the patient group compared to those of the controls. This study showed a decreased activation in inferior fontal (BA 47), middle frontal (BA 6), and superior temporal (BA 22/38) neural networks from the patient group and confirmed the earlier findings on the impaired working memory of schizophrenic patients in the fMRI investigation.