Nearly all chronic anal fissures occur in the posterior midline of the anal canal. However, some of them are in the anterior midline and are rarely double or in the lateral anal walls. The aim of this study was to determine if the clinical, manometric and endosonographic characteristics in patients with chronic anal fissure varied according to topography of the fissure. The patients included in this prospective study were divided according to a fissure site in posterior midline location (Group A, n = 84) and anterior midline location (Group B, n = 30). No differences were found regarding clinical data except that anterior fissures were more common in females. Mean maximal anal resting pressure and internal anal sphincter thickness was higher in Group A. However, these differences were not statistically significant. We found correlation between mean maximal anal resting pressure and internal anal sphincter thickness in patients suffering from anterior chronic anal fissure.