Primary actinomycosis of the breast is a very rare disease and most commonly caused by Actinomyces israelii which normally inhabits mouth, colon, and vagina. Primary forms directly affect the breast but the etiology is unknown. Possible causes include infection of the lactiferous ducts due to trauma during breast feeding or kissing. In secondary actinomycosis, the infection at the primary sight ultimately reaches the breast. The purpose of the study is to present, in detail, a case of a 50 year old woman, with the complaint of swelling in the right breast of 6 months duration which was variable in size and associated with discharging sinuses.