Cognitive dysfunction is a well-documented feature of schizophrenia (SZ) and bipolar (BD) disorder. The person's subjective experience of cognitive difficulties is less investigated. Here we investigated subjective cognition in SZ and BD compared to healthy controls (HC). Subjective and objective cognition were assessed in 91 SZ participants, 55 BD participants and 55 HC, applying a novel measure of subjective cognition, the self-assessed cognitive complaints scale (SACCS) and a clinically relevant neuropsychological test battery. The psychometric properties of SACCS were investigated. The relationship between subjective and objective cognition, and subjective cognition and clinical variables were explored in SZ and BD. The SACCS showed adequate psychometric properties. Clinical groups reported significantly more cognitive complaints than HCs, without differences between SZ and BD. There were no significant associations between subjective and objective cognitive measures. There was a small trend association between subjective cognition and insight in SZ participants, and moderate sized associations between subjective cognition and general psychopathology and functioning in BD participants. Although SZ participants are more cognitively impaired than BD participants, the two groups report similar levels of subjective cognitive complaints, with no association between subjective and objective cognition. Our results suggest that the expression of subjective cognition is associated with different clinical factors in SZ and BD.