Objective:To explore the role of the adenoid and tonsil in children with sleep apnea hypopnea syndrome(OSAHS). Methods:94 children with OSAHS were diagnosed by polysomnography (PSG) and the tonsil and adenoid size were evaluated. The data were analysed statistically. Results:29 cases (30.85%) had adenoid hypertrophy,and 8 cases(8.51%) had tonsil hypertrophy,52 cases(55.32%) had both adenoid and tonsil hypertrophy,5 cases(5.32%) had neither adenoid hypertrophy nor tonsil hypertrophy. The differences among only tonsil hypertrophy patients,only adenoid hypertrophy and both adenoid and tonsil hypertrophy on AHI,LSaO2 were significant(P < 0.05). The difference between only adenoid hypertrophy patients and both adenoid and tonsil hypertrophy patients was not significant(P > 0.05). The differences on AHI in different level groups of tonsil grade were not significant. The differences on AHI in different level groups of adenoid grade were significant. The R value of correction between the adenoid and AHI was 0.522. The R value of correction between the tonsil and AHI was 0.125. Conclusion:The adenoid hypertrophy has a positive relationship with OSAHS,but the tonsil hypertrophy is not relative with OSAHS. Synchronous hypertrophy of adenoid and tonsil can increase the incidence of OSAHS.