Atresia ani (AA) is a congenital defect that occurs when the anal membrane is not perforated and becomes permanent. However, it is worthwhile to note that it is not very common in cats. This case report consists of a 2 month old male Persian cat with Type I AA, who was brought to our clinic with the complaint of defecation from a very narrow opening since birth. In the clinical examination of the patient, abdominal distention and swelling around the anus were detected. The patient was constantly taking a defecation position and had difficulty defecating. Contrast radiography was taken with the retrograde method, and the obstruction in the anus was detected resulting in the decision of performing an operation. The aim of surgical intervention is to maintain anorectal continuity as well as preserving the external anal sphincter and colon function. Surgical treatment should be promptly performed before chronic and prolonged distention, colonic atony or megacolon associated with possible urinary tract infection occurs. The patient was placed on the table in the prone position and the narrowed part of the rectum was treated by resecting it with 3600 anoplasty. Having lowered the rectal mucosa distally, the mucosa and skin were brought together, and then sutured with synthetic non-absorbable monofilament 4/0 suture material. Extra care was taken to preserve the external anal sphincter and anal sacs during dissection.