Objective:To evaluate the effect of acupuncture treatment on semen parameters and the proportion of mature and functional sperm as measured by using sperm-hyaluronan binding assay (HBA) in subfertile Singapore men.Methods:Singaporean male subjects undergoing subfertility investigation were enrolled prospectively in this pilot study. Each subject received acupuncture treatment at fixed acupoints and two acupuncture sessions per week for 10 weeks. A total of five semen samples were obtained from each subject at 5 weekly intervals up to 20 weeks of the study; at Pre-treatment, Treatment 1 (5th week), Treatment 2 (10th week), Post-treatment 1 (15th week) and Post-treatment 2 (20th week). Semen analysis was performed to assess semen parameters and HBA score (percentage of motile sperm bound to hyaluronan) to determine the proportion of mature and functional sperm.Results: Mean HBA scores improved significantly from 12.0% at Pre-treatment, to 18.4% (P=0.03) at 5th week and was 16.8% (P=0.07) at 10th week of acupuncture treatment. After completion of acupuncture treatment, HBA scores continued to increase significantly to 25.8% (P <0.001) at Post-treatment 1. At Post-treatment 2, HBA scores decreased to 16.3%. Sperm concentration showed similar trend but it was not statistically significant. Other semen parameters remained unchanged throughout the study period.Conclusions:HBA scores increased significantly during the first 5 weeks of acupuncture treatment (Treatment 1) and 5 weeks after the completion of treatment (Post-treatment 1). Hence acupuncture treatment was effective in increasing the proportion of mature and functional sperm but had no effect on other semen parameters.