Aim The aim of the present study is to evaluate the fertility outcomes of intracytoplasmic sperm injection (ICSI) as well as sperm count, motility and morphology in couples with infertile male partners exhibiting idiopathic oligoasthenozoospermia (OA) and treated with tamoxifen citrate and/or L-carnitine. Materials and methods In this randomized controlled trail, couples with female cause of infertility were excluded. Only couples with male cause of infertility with idiopathic OA were admitted to this study and randomly assigned into four different groups of treatments as follow: Group A (n = 45) received an anti-estrogen compound (tamoxifen 20 mg/day), group B (n = 20) received L-carnitine (1000 mg/day), group C (n = 34) received tamoxifen 20 mg/day plus L-carnitine 1000 mg/day, whereas group D (n = 29) received placebo. Treatments were continued for 3 to 6 months. Results Treatment groups of A, B, and C showed an overall improvement in the tested parameters of sperm when compared to the control group that showed an overall reduction in those parameters after termination of the treatment. In this context, sperm count increased from 7.58 ± 2.93 × 106/ml before treatment to 10.81 ± 1.84 × 106/ml after treatment in group A (p = 0.016). Similarly, sperm count increased from 5.32 ± 2.09 × 106/ml to 8.92 ± 2.29 × 106/ml in group C (p = 0.01). Patients from group C did not only have an improved total motility of sperm from 8.03 ± 1.59% to 13.78 ± 3.85% (p = 0.045) but also an improved sperm normal morphology from 0.88 ± 0.45% to 1.99 ± 0.71% (p = 0.026). Patients from group A or C exhibited an improved ICSI outcomes when compared to those in patients from group B or D (48.9 or 48.3 vs 16.6 or 20, respectively, p = 0.46). Conclusion It is concluded that administration of tamoxifen and L-carnitine can improve both sperm parameters of fertility and ICSI outcomes. Combined tamoxifen and L-carnitine treatments result in maximum therapeutic effect in men with idiopathic OA. How to cite this article Haje M, Naoom K. Combined Tamoxifen and L-Carnitine Therapies for the Treatment of Idiopathic Male Infertility Attending Intracytoplasmic Sperm Injection: A Randomized Controlled Trial. Int J Infertil Fetal Med 2015;6(1):20-24.