OBJECTIVE:: To compare quality of life and fertility aspects after laparoscopic inguinal hernia repair in men using a heavyweight or lightweight mesh. SUMMARY BACKGROUND DATA:: The use of lightweight meshes in laparoscopic inguinal hernia repair could have beneficial effects on quality of life and preservation of the spermatic structures due to a decreased foreign-body reaction. METHODS:: A total of 59 male patients planned for primary, unilateral or bilateral inguinal hernia repair were randomized between a standard polypropylene (Marlex) or lightweight mesh (Vypro II, TiMesh). Main outcome measures were fertility aspects, assessed preoperatively and at 1-year follow-up by semen analysis and scrotal ultrasonography. Secondary outcomes were quality of life (SF-36 and McGill Pain Questionnaire) and recurrence up to 1 year postoperatively. RESULTS:: Patients operated on with a VyproII or TiMesh mesh exhibited a decreased sperm motility (vs. preoperatively) compared with Marlex patients, respectively -9.5% and -5.5% versus +2% (P = 0.013). When the results after uni- and bilateral hernia repair were analyzed separately, this difference only remained significant in the bilateral hernia subgroup: -10% for VyproII and -17% for TiMesh versus +1% for Marlex (P = 0.037). Other fertility parameters (sperm concentration, morphology, and alpha-glucosidase level) were unchanged. There were no differences at any study point between the 3 groups regarding quality of life. Only for resumption of sport activities was a small advantage noted for VyproII versus Marlex patients (P = 0.045). After 1 year, no recurrences were observed; 3 patients (6%) complained of chronic disabling pain. CONCLUSIONS:: Our data suggest that the use of lightweight meshes for laparoscopic inguinal hernia repair in male patients negatively influences sperm motility, without any benefit on quality of life. These alterations might be important in a subgroup of young male patients operated on laparoscopically for a bilateral hernia. This study was registered in the clinicaltrials.gov database (ID number NCT00925067).