Actinomycosis is the most misdiagnosed disease so far, though it is known to clinicians since 150 years. Primary perianal actinomycosis is extremly rare. The infection is caused by the bacterium Actinomyces, gram positive bacilli of the Actinomycetales genus, and A. israelii is responsible for the majority of human disease, which often is a saprophyte. Male gender and diabetes are risk factors. Patients, who have undergone appendicectomy, have had a missed perforated appendicitis or women with a history of intrauterine contraceptive device use are at an increased risk. The diagnosis is a challenge and often delayed, with a protracted history of masses and sinuses extending into the gluteal, urogenital and anorectal region. The diagnosis is suspected by the observation of draining sulfur granules and promptly confirmed by histology .These findings are contrasting with the classic picture of perianal actinomycosis. It is concluded that perianal actinomycosis can occur in the absence of risk factors and that early diagnosis requires a high degree of suspicion. An infection with Actinomyces should be suspected in the presence of lesions containing watery purulent material with sulfur granules. It gives unusual tumoral lesions with abcesses & fistulas. Cope in 1949 said: -"Actinomycosis occurs so seldom in the colon and the rectum that no surgeon, even if he be a proctologist is likely in a life time to see more than a few cases". An anorectal actinomycosis case can mimic rectal cancer .Florid abscess formation with fistulation, abundant granulation and dense surrounding fibrosis are common. Diagnosis prior to, or even during, surgery is rare and the findings are usually mistaken for acute inflammatory pathologies or malignancy. The treatment, a combination of surgery and antibiotics [penicillin], is poorly standardized. Recurrences are possible. So the condition remains a challenge over the century, but it can be overcome by an integrated approach.