The highveld mole‐rat, Cryptomys hottentous pretoriae is a social, subterranean, co‐operative breeder with a high reproductive skew. The relationship between reproductive status and reproductive physiology in male highveld mole‐rats was investigated. Testicular morphometrics, histological parameters, plasma testosterone concentrations and sperm motility parameters were studied in 31 males (14 reproductive and 17 non‐reproductive males). Reproductive males were significantly larger than non‐reproductive males, with testicular mass and volume corrected for body mass considerably larger for the reproductive males. Circulating plasma testosterone concentrations of reproductive males were not significantly higher than non‐reproductive males (reproductive males 10.3±1.8 nmol l−1vs non‐reproductive males 7.3±1.74 nmol l−1). Sperm motility parameters were measured, but no significant differences were found between reproductive and non‐reproductive males. All 14 reproductive males had motile sperm, whereas 13 of the 17 (76%) of non‐reproductive males possessed motile sperm. A typical ejaculate of a reproductive male contains 48.3% motile sperm characterized by a high percentage of flagellar defects, whereas the non‐reproductive male has an ejaculate containing 45.6% motile sperm with a high percentage of head defects. It is apparent that non‐reproductive males are not physiologically suppressed from reproducing. Moreover, the non‐reproductive males are excluded from incestuous matings as a result of being the offspring of the reproductive female.