Updated project metadata. The aim of this study was to achieve a higher resolution of the human sperm proteome for better understanding of the molecular causes of male infertility. For this purpose, we examined the proteomic profiles of sperm from 76 men for proteins with deregulated abundances. Infertile men had abnormal semen parameters and were involuntarily childless. Men in the cohort with normal fertility had normozoospermia and had fathered children without medical assistance. Mass spectrometry analysis led to an in-depth reconstruction of the human sperm proteome. The corresponding genes were mainly involved in cellular motility, response to stimuli, adhesion, and reproduction. We also observed increasing numbers of at least three-fold differentially abundant sperm proteins from oligozoospermia and oligoasthenozoospermia to oligoasthenoteratozoospermia, compared with normozoospermia. Primarily, flagellar assembly and sperm motility, sperm-egg interaction, and male gametogenesis were affected. This suggests that sperm of infertile men carry signatures of impaired sperm production and are functionally impaired. Not least, we present new male infertility markers in addition to established ones.