Objective To probe the significance of application of ultrasound biomicroscopy (UBM) in the diagnosis and management of the iris and ciliary tumors. Methods UBM (Mode 840, Humphrey, 50 MHz 5 mm×5 mm) was done in 34 cases (35 eyes) of iris and ciliary body tumors, and some of the affected eyes underwent B-scan or Doppler ultrasound and CT scan. Histopathological examination of the resected tumor tissues was performed in 21 eyes of the operation. Results Among this series of 35 eyes with iris and ciliary body tumors detected by UBM, the characteristics of locality and solidity of the tumors, i,e., anterior chamber in plantation cyst, cyst behind the iris, and solid tumors of iris and ciliary body, of 21 eyes undergone surgical treatment revealed the same results both in UBM and histopathological examinations. Conclusion UBM can supply precise informations in diagnosis and treatment of tumors of iris and ciliary body. (Chin J Ocul Fundus Dis, 2002, 18: 128-130)