Background: Hyperprolactinemia is a condition of elevated serum prolactin. Prolactin is a 198-amino acid protein (23-kD) produced in the lactotrophs cells of the anterior pituitary gland. Hyperprolactinemia is the most common hypothalamo-pitiutary disorder; it can also occur secondary to use of some drugs, chronic illnesses like hypothyroidism, chronic liver and kidney disease, stress and neurogenic disorders. Idiopathic Hyperprolactinemia refers to elevation of serum prolactin in the absence of the above conditions. Objective: The aim of this study is to explain scientifically hyperprolactinemia as a cause of female primary infertility and its prevalence in GeziraState, Central Sudan. Method: Serum prolactin, FSH and LH levels were estimated using commercially specific enzyme immunoassay (EIA) technique in serum from 200 women (150 primary infertile and 50 fertile non-pregnant and non-lactating) attending Wad Medani teaching hospital in Wad Medani city, Central Sudan, from 2011 till 2013.   Results: Hyperprolactinemia was found in 33.3%, irregular menstrual cycle 66%, amenorrhea 6.7%, oligomenorrhoea 59.3%, normal menorrhea (33,3%) and galactorrhoea 3.3% of primary infertile women. Conclusion: The prevalence of hyperprolactinemia was about one-third of primary infertile women in GeziraState (Central Sudan). The mainaetiology ofprimary infertility was anovulatory cycle due to high level of prolactin.