INTRODUCTION: Schizophrenia patients, particularly those with specific types of hallucinations and delusions, may have a deficit in monitoring the generation of thought. This deficit, termed autonoetic agnosia, may result in the conclusion that self-generated thoughts come from an external source. METHODS: This study assessed autonoetic agnosia in 29 schizophrenic patients and 19 controls by applying a recently developed technique from cognitive science: multinomial modeling of source-monitoring data. RESULTS: Schizophrenic patients demonstrated deficits in monitoring the source of self-generated information, yet performed similarly to controls in monitoring the source of visual and auditory information. Schizophrenic patients with specific "target" symptoms such as auditory hallucinations and thought insertion had greater deficits than other patients in recognizing self-generated information. CONCLUSION: This study offers partial support for the notion that schizophrenic patients manifest autonoetic agnosia.