ABSTRACTBackground: Fertility traits in pigsmade a restricted progress through traditional selection. Applying marker assisted selectioncould improve these traits. The aim of the study was to investigate the effects of candidate genes Estrogen Receptor (ESR), FollicleStimulating Hormone Beta (FSHB) and Prolactin Receptor (PRLR) on sperm quality traits of Landrace and Yorkshire boars undertropical conditions in Northern Vietnam.Methods: A total of 6306 ejaculates from 140 boars (92 Landrace and 48 Yorkshire) were collected to estimate sperm ejaculatevolume (VOL), spermatozoon motility (MO), sperm concentration (CO) and total number of spermatozoon in ejaculate (NT). Eartissue samples were collected for genotype identification of SNP present in ESR, FSHB and PRLR genes using PCR-RFLP technique.A mixed model was used to test the effect of different genetic and non-genetic factors on the sperm quality traits.Result:The genotype frequencies of ESR, FSHB and PRLR were in Hardy-Weinberg equilibrium for each breed. Age of boars andmonth of the year had significant effect on all the sperm quality traits (P<0.01) while effect of breed was found to be non-significant onall the sperm quality trait. FSHB gene significantly (P<0.05) affected VOL, MO and CO. Boars with BB genotype showed positiveeffect on VOL but negative effect on MO and CO in comparison with AA genotype boars. ESR gene showed only effect on VOL whilePRLR affected only MO. Boars with AA and AB genotypes of ESR gene had a significantly higher VOL than those with BB genotype(P<0.05). For PRLR gen, AB genotype was associated with higher MO than AA genotype (P<0.05). These results suggest a possibilityof using the existing polymorphisms in ESR, FSHB and PRLR genes to improve some sperm traits of Landrace and Yorkshire boars.