The Book consists from 4 chapters, First one discusses the introduction about the infertility in term of types, causes, pathophysiology and treatment in addition to some information about the L-carnitine and its use in treatment of male sub infertility and literature review about this subject. The Second chapter talks about the materials and patients' information and the collected data in this work. The Third chapter talks about the results of this work and the comparison with the same work. The Fourth chapter was discussing the results of this study and the recommendation for the next trials.