The prevalence and clinical significance of mucosal epithelial proliferation or hyperplasia of the fallopian tube are controversial in the few studies reported. Some authors have retrospectively examined "routine" sections (one or two submitted from each tube), whereas others have prospectively blocked the entire tubes. In the current study, we prospectively studied a total of 168 tubes from 98 women who had various indications for salpingectomy and compared the diagnosis in an initial single section (to simulate the usual practice) with that in the remainder of the entirely sectioned and submitted tube (mean total number of sections, 9.0). Some degree of mucosal epithelial proliferation was found in 83% of all tubes examined, with no difference between the tubes removed for routine tubal ligation and those in women who had benign ovarian lesions, malignant gynecologic tumors, uterine leiomyomata, or benign tubal lesions (salpingitis or ectopic pregnancy). Mucosal epithelial proliferation graded as more than mild, however, was seen in only 4.5% of the otherwise normal ligated tubes versus 35 to 46% of tubes associated with the other lesions. When the initial sections were compared with the subsequent ones, the diagnosis was identical in 96 tubes (57%). In the other 72 tubes (43%), the difference in diagnosis was never greater than one grade (no, mild, moderate, severe mucosal epithelial proliferation), with the diagnosis more often upgraded (50 tubes) than downgraded (22 tubes) in the additional sections. It is concluded that there is no reason to submit an entire tube for histologic examination to detect clinically significant lesions, and the usual practice of submission of one or two sections is clinically appropriate.