Although both DSM-IV and ICD-10 define schizoaffective mixed states, they have not received much attention-neither in the clinical nor in research context. We present preliminary results of a prospective study of bipolar affective (n = 100) and bipolar schizoaffective (n = 177) patients. 25% of the bipolar affective and 32% of the bipolar schizoaffective patients had at least one (schizo)mixed episode during the illness course. Nevertheless, (schizo)mixed episodes were rare-only 5.6% of all episodes. There was a trend that patients with (schizo)mixed episodes were more often women and exhibited more disability (reflected by higher rates of disability payments). Nevertheless, these differences failed to reach significance. Overall, schizo-mixed episodes are as frequent as "pure" affective mixed episodes. They might be linked to a less favourable course. Nevertheless, while their diagnostic criteria are problematic, they are systematically underdiagnosed.