Fertility as a fundamental trait in dairy cattle breeding is under consideration for decades and gaining economic in the recent years. In current study, linear animal models were used to estimate (co) variance components, heritabilities, genetic and phenotypic correlations for reproduction traits for different milk production levels. Estimated breeding values and phenotypic records were used to evaluate genetic and phenotypic trends. Age at first service (AFS), and first calving (AFC), calving interval (CI), open days (OD), days to first service (DFS), interval between first and last insemination (IFL), conception rate (CR), insemination number per service (INS) and milk yield (MY) were studied. Different levels of milk production were assigned as low production (less than 7000 kg), medium production (greater than 7000 kg and less than 9000 kg) and high production (greater than 9000 kg). A total number of 159023 records from first parity during 1982 to 2006 and a total number of 211551 records in secondary parity during 1997 to 2008 were used. The data collected from Animal Breeding Center of Iran. First, fixed variables with significant effect on the traits were detected using fixed models. Then, according to the restricted maximum likelihood (REML) method, different mixed models were considered to estimate genetic parameters. Heritabilities for reproductive traits were below than 0.10. Estimated heritability coefficient for milk production was 0.33. The results showed strong genetic correlations between reproductive traits (till 0.90). The Maximum value of the correlations was related to CI and OD (0.90), DFS and CR (-0.91). The minimum correlation was obtained between DFS and IFL (0.025). Genetic and phenotypic correlations between reproductive traits and milk production at different levels indicated significantly high correlation between reproductive traits and milk production in all reproductive traits (except IFL and DFS) in low producing dairy cows compared to other milk production groups. Estimated phenotypic and genetic trends for milk production and reproductive traits indicated that selection has been done to improve milk production. Reproductive traits except calving interval has increased the trends, while phenotypic trend of these traits was negative, that showed environmental factors might be controlled.