The role of general anxiety measured by the Hospital Anxiety and Depression Scale (HADS), or the Spielberger Trait Anxiety scale, (STAI‐T) on dental anxiety (measured by the Corah Dental Anxiety Scale, the Kent Phobia Scale and by analogue ratings concerning specific procedures) of dentally phobic patients was examined using multiple regression analysis. HADS anxiety and STAI‐T scores were both significant predictors of Corah scores; whereas HADS depression and STAI‐T predicted Kent scores, which measure how concerns about dentistry affect emotional and social well‐being. Fear of coming for an appointment significantly contributed to both scores and was itself predicted by anxiety about having an instrument in the mouth. The effects of sedation with nitrous oxide or midazolam on the change in dental anxiety after two treatment sessions in patients with high or low HADS anxiety were compared. Both drugs resulted in significant and equal reductions in scores on the Corah scale and anxieties about an instrument in the mouth, drilling and filling, in both high and low anxiety groups. None of the groups showed a significant reduction in scores on the Kent scale or in fear of coming for an appointment.