The aim of this study was to verify the efficacy of a programme for dental plaque control in autistics. Patients were evaluated on five occasions over a period of 180 days using the following instruments: OHI-S, DMF-T, the Fonnes brushing technique and diet questionnaire. Participants were divided into two groups according to level of co-operation on the programme: Group A (co-operative) and Group B (non-cooperative). A statistically significant improvement (p less than 0.001) in Oral Hygiene was attained, with 84.2% showing regular or satisfactory hygiene at study end-point. Conclusion: Groups A and B both showed improvement in hygiene (p less than 0.001 and p = 0.004), but improvement was significantly higher among co-operative patients (p less than 0.001 at 180 days), who also had a higher mean age (p = 0.02).