Background: Infertility is one of the most common female diseases and it is defined as the inability of getting pregnant after trying for more than one year, without use of birth control means and while having normal sexual intercourse. Aim: This study aims at evaluating of phospho extracellular signal regulated kinase p(ERK1/2) as a biomarker in serum and urine of infertile women and its correlation with age. Patients and Methods: A case control study was carried out in Tikrit Teaching Hospital in Salahdeen Governorate ¿ Iraq, from first November 2013 to the end of April 2014. In this study, forty-six women (25 infertile married women and 21 apparently healthy women considered as control); their ages range from 15 to 40 years, were collected to investigate their p(ERK1/2) concentration in serum and urine by using enzyme linked immunosorbent assay (ELISA) technique.