Background: Many infertile men have disorders correctable with the use of medication, and if diagnosed and treated properly, natural fertilization can be attained. Objective: To evaluate the effect of ALA on semen parameters in idiopathic asthenozoospermia. Patients and methods: This was a case-control study, including 80 patients presenting with primary infertility enrolled from outpatient Andrology Clinic Units of Al-Azhar University Hospitals. Patients were divided into two equal groups. One group was given oral ALA tablets at a dose of 300 mg twice/day, whereas the other group was given a placebo twice daily. The duration of the study ranged from March 2020 till September 2020. Results: There was a significant difference between 2 groups as regard total motility after treatment progressive motility after treatment, and % vitality after treatment. Conclusion: Medical therapy of asthenoteratospermia with ALA supplement could improve quality of semen parameters.