Until recently, research concerning fertility and ageing has mainly been focused upon the female reproductive system. Reproductive ageing in the male is a less explored field, but increasing evidence suggests that paternal age is highly relevant to a couple’s fertility and the outcome of pregnancy. Studies have linked increased paternal age to longer time-topregnancy, more frequent spontaneous abortions and increased risk of certain diseases in the offspring, such as schizophrenia. The effects of male reproductive ageing are also getting more important, as the age of fathers-to-be is rising in our society. The aim of our study was to investigate the relationship between age and the sperm parameters DNA-fragmentation, DNA-stain-ability and rapid progressive motile spermatozoa. The population was 9835 men undergoing infertility evaluation at Rikshospitalet in the period 2004-2011. DNAfragmentation and rapid progressive motile spermatozoa were found to decline significantly with increasing age, while DNA-stain-ability was significantly rising. The analysis alsosuggests a more rapid change in DNA-fragmentation after the age of 45 years, which might be indicative of acceleration in male reproductive ageing with similarities to that found in women. This is an interesting finding and in accordance with some theories about ageing in general. Our study concludes that there is a relationship between paternal age and selected sperm parameters, but more research is needed to evaluate the mechanisms behind male reproductive ageing and its clinical consequences.