Summary: A series of 34 patients who underwent a total of 37 ultrasound-guided cyst punctures and fine needle biopsies for diagnosis and treatment of pelvic lesions are reported. In all but 1 patient the lesion visualized was entered and cytological diagnosis was achieved, although 1 patient required a second attempt under general anaethesia. Seven cysts were endometriotic; these and all the remaining cysts were benign and only 4 patients developed a recurrence of the cyst following puncture. No patient in whom the ultrasound appearance suggested a benign cyst was found to have an ovarian malignancy. Three patients with malignant lesions had a total of 4 punctures or biopsies and a final patient had a fine needle biopsy of an ovary to exclude malignancy.