This work will focus on the effect of Anastrozole on both seminal and serum lactate, pyruvate, and L/P molar ratio in male with infertility and the correlation between these parameters to age and BMI of patients. This study is a prospective observational study conducted in Iraq from June 2020 to January 2021. Thirty-five patients referred from different general /or private infertility clinics with infertility for at least one year to the Orkida-private Laboratory-Mosul. Patient’s age ranging from 20-44 years with a mean of (29.7±6.2). Patients present with BMI range from 21-38 with a mean (27.7±5.5). All patients referred to their full history review notes about their clinical examination and laboratory investigations. The patient treated with 1mg Anastrozole once daily for 28 days from the company for serum and seminal samples collected before starting the treatment and after 29 days. Semen samples collected after 3-5 days of sexual abstinence and the standard manual semen analysis performed according to the WHO guidelines. Mitochondrial function analysis involved measurement of serum and seminal lactate and pyruvate by fluorescence-based methods of Cayman chemicals (700510 and 700470 respectively) and L-Carnitine was assayed using colourimetric/fluorometric MyBioSource (MBS841446) after standard curve was established. Data represented as mean ± SE. The results of this work show that after treatment Anastrozole serum lactate (22.4%) and lactate/pyruvate molar ratio (16.2%), seminal lactate (26.5%), pyruvate (16.3%) and lactate/pyruvate molar ratio (11.7%) significantly reduced after the treatment (p≤0.01) Both serum and seminal L-Carnitine levels significantly increase by (19% and 18% respectively) after the treatment with Anastrozole p≤0.01. Anastrozole significantly elevates mitochondrial function lower both serum and seminal lactate and pyruvate after 28 days of treatment.