Background: Chronic anal fissure (CAF), which affects both sexes equally, typically develops in early adulthood. For the therapy of CAF, laser sphincterolysis and botulinum toxin (BTX) have been used. Objective: The aim of the present study was to evaluate the effectiveness of BTX injection and laser in the treatment of CAF. Patients and methods: Our clinical trial included 150 patients with CAF and assigned into one of the 3 modalities of treatment: lateral internal sphincterotomy (50 patients, BTX (50 patients) and laser sphincterolysis (50 patients). In BTX group, 20 U was diluted in 1ml isotonic saline and half of this dose was injected on each side of the fissure in all cases. Regarding laser sphincterolysis, all procedures were carried out using the Lasotronix Smart M 1470 nm diode laser (Poland); for Anal fissure 70-100 W energy given. Patients were followed up after 1 week then every 2 weeks for 8 weeks after intervention. Results: All cases in all groups stayed for one day at hospital. Healing period was significantly shorter among Botox group then laser group and significantly longer among open group. In BTX group, 7.5% of the patients were reinjected with the same dose of botulinum toxin and had healed fissure 2 months after reinjection. Incontinence was significantly associated with open group and was lower in laser and Botox groups with no significant difference between them. Conclusion: BTX injection is more suitable first-line treatment of choice for chronic idiopathic anal fissure, which is not associated with other anal conditions. It is a simple procedure, easy to learn and can be done in outpatient clinic without need for sedation or local anesthesia. Regarding laser, it has less operation time, discharge may be given within a few hours, within a day patients can go back to normal routine work, with greater surgical precision and fastest recovery, fewer blood loss during surgery and no or minimal post-operative pain.