Addition of prostaglandin F2alpha (PGF2alpha) to extended boar semen has been shown to slightly increase reproductive parameters in sows such as the conception rate and the total number of piglets born alive. The mechanisms by which PGF2alpha affect these parameters have not yet been elucidated, but it is possible that the sperm transport after insemination is increased. This study investigated whether the sperm motility from 20 Piétrain boars improved when PGF2alpha (Dinolytic; 5 mg PGF2alpha/ml) was added to diluted semen. Different amounts of PGF2alpha (0, 0.5, 1 and 2 ml/100 ml) were tested and the motility was evaluated immediately after addition of PGF2alpha, after 30 min, 2 h, and 24 h. Two computer-assisted semen analysis (CASA) systems, namely the Sperm Quality Analyzer (SQA-IIC) and the Hamilton Thorne (HTR Ceros 12.1) were used to assess the motility parameters. With the SQA-IIC, sperm motility index values of the treated groups were only slightly higher (P>0.05) compared to the negative control group. The different motility parameters measured with the HTR Ceros 12.1 were similar between the treatment groups, except for beat cross frequency, which was higher in the control group (1.5-5%; P<0.001). This study documented that the addition of 2.5, 5 or 10 mg PGF2alpha to 100 ml diluted boar sperm does not increase any sperm motility parameter. Further research is necessary to elucidate mechanisms by which PGF2alpha in diluted semen may improve the reproductive performance in swine farms.