Oestrogen biosynthesis in ejaculated spermatozoa is an autonomous process, which may influence sperm functions. The purpose of this study was to evaluate the relationship between the expression of aromatase, sperm quality and seminal neutral α-glucosidase marker in semen of Tunisian infertile men: asthenozoospermia (A; n = 16), teratozoospermia (T; n = 12) and asthenoteratozoospermia (AT; n = 11) in comparison with 18 normozoospermic ones. Aromatase mRNA levels estimated by real-time PCR were reduced in groups T (52%) and AT (67%) compared to controls and inversely correlated with the percentage of normal forms. A higher coefficient of correlation was noted in presence of microcephaly or acrosome malformations (r = -0.64). The asthenozoospermic group was divided into two subgroups according to the relative amount of aromatase. The subgroup (A2) with higher aromatase transcript level was associated with an increased seminal pH, a decreased sperm viability, low sperm percentage motility and low neutral α-glucosidase semen levels. Our data highlight the involvement of aromatase in motility and morphology of spermatozoa. Thus, this enzyme could bring new insights about quality and fertilising capacity of human spermatozoa.