The aim of this study was to investigate the relationship between growth hormone, releasing hormone (GHRH) and prolactin hormone (PRL) genes polymorphisms and 305 day milk yield in Hostein dairy cattle reared in Turkey. Overall, 150 Hostein dairy cows was used for the study. In order to determine GHRH genotypes. obtained PCR products were restricted via HaeIII enzyme and to determine PRL genotypes. obtained PCR products were restricted via Rsal enzyme. The mean differences of 305-day milk yield among the genotype groups of GHRH and PRI, genes were assessed by analysis of variance (ANOVA). Two alleles (A and B) and three genotypes (AA, AB and BB) for GHRH-HaeIII polymorphism were observed in examined Hostein cows. The frequency of the A and B alleles was found to be 0.32 and 0.68. respectively in examined Hostein cows. Two alleles (A and B) and three genotypes (AA, AB and 1313) for PRI, RsaI polymorphism were observed. The frequency of the A and B alleles was found to be 0.86 and 0.14, respectively. Finally, GHRH-HaeIII and PEL-Rsal genotype effects on daily and lactation milk yield was not found to be significant in examined animals.