Botulinum toxin type A (BTX-A) is the precise drug to cause temporary paralysis of extraocular muscles and change ocular alignment with few side effects. Congenital esotropia is an ocular misalignment characterized by a convergent non-accommodative ocular deviation which develops at approximately six months of age. Botulinum toxin type A has been used in congenital esotropia as an alternative treatment to surgery.In this study, we report three cases of large angle congenital esotropiamore than 45 prismdiopter (PD)underwent BTX-A injection simultaneously on both medial rectus muscles. The procedure was done under total intravenous anesthesia (TIVA) with upright position. A unit of BTX-A in 0.1 mililiter was injected through the intact conjunctiva into the medial rectus muscle. Two weeks after injection, two patients developed exotropiaand one patient developed ptosis. Four months after injection, all the cases showed improvement in ocular alignment (less than 35 PD) with no other complication. Botulinum toxin type Ainjection represents a secure alternative procedurein case of congenital esotropia and reduce the angle of deviation before surgical interventions were planned.