A deficit in social cognition including theory of mind (ToM) is one of the most disabling clinical characteristics of schizophrenia. Very few studies have investigated these impairments in schizophrenia during natural communication situations (McCabe et al. 2004, Champagne-Lavau et al. 2009). Recent findings have shown that people with schizophrenia (SZ) may be more or less impaired in their ToM skills (Pickup and Frith, 2001; Champagne-Lavau et al., 2009; Brüne and Schaub, 2012). Indeed, 50% to 80% of SZ patients may show difficulties to attribute mental states (Brüne & Schaub, 2012). Using a classical ToM task (i.e. MSAT), Brüne & Schaub (2012) showed that, by comparison to SZ patients with fair ToM abilities, SZ patients with poor ToM abilities were characterized by social behavioral abnormalities, disorganization and excitement symptoms, with absence of executive dysfunction. However, observing a social interaction is not equivalent to participating in a social interaction in terms of the cognitive processes involved in the attribution of mental states to other. Thus, the aim of the present study was to examine characteristics of relatively impaired SZ patients (SZ-I) and relatively unimpaired SZ patients (SZ-U) on a ToM task assessing attribution of knowledge during a situation of conversation.