Individuals with persecutory delusions have been reported to make external and stable attributions for negative events and to have a tendency towards internal attributions for positive events. It remains unclear whether this abnormality is present in individuals with non-persecutory delusions. Using the Attributional Style Questionnaire, we assessed the attributional style of 19 individuals with persecutory or grandiose delusions (PG), 12 individuals whose delusional beliefs were non-persecutory and non-grandiose (NPG) and 24 controls. The PG group displayed externality in their causal attributions for bad events but those in the NPG group did not differ from controls. Both deluded groups were significantly more stable in their attributions for bad events in comparison to controls. Such findings argue against a primary role for attributional biases in the genesis of delusions, although a role in shaping delusional content and maintaining the disorder and a role for external attributions in defending against reductions in self-esteem cannot be excluded.