The objective of this study was to evaluate the relationships between body condition score (BCS) and milk production traits using the data collected by the cooperative union in Isfahan province, During the years 2006 to 2014 was conducted on 16 herds. Used data from 27135 animals to be the first lactation records for BCS, milk production, fat percentage of milk, protein percentage of milk, somatic cell score (SCS) of milk and the fat to protein ratio of milk (FPR) and each traits of 85582, 203568, 171244, 175757, 191451 and 170810 records respectively. After preparing and editing the information required, prepare files for production, and the pedigree was Estimates of genetic parameters such as heritability and correlation of by two trait models of two methods is continuously and non-continuous for BCS using random regression animal model by test day records. All analyzes was performed by the DMU software. According to recorded history, the number of 24125, 20136, 20597, 23278 and 19975 respectively, the number of records for milk yield, fat percentage of milk, protein percentage of milk, SCS, and FPR is equal to BCS recorded history traits. Average heritability of traits, milk yield, fat percentage of milk, protein percentage of milk, SCS and FPR in the methods by continuously for BCS is 0.09, 0.12, 0.08, 0.09, 0.03 and 0.06 respectively, as well as in the methods by non-continuously for BCS was for BCS is 0.033, 0.18, 0.09, 0.1, 0.06, 0.11, respectively. Average genetic correlations between BCS and first lactation milk yield, fat percentage of milk, protein percentage of milk, SCS and FPR in the methods by continuously for BCS is -0.4, 0.09, 0.15, 0.00 and 0. 04 and methods by non-contiguous for BCS is -0.2, 0.07, 0.13, 0.02 and 0.02 And the average permanent environment correlation between BCS and first lactation milk yield, fat percentage of milk, protein percentage of milk, SCS, and FPR is -0.064, 0.18, 0.256, 0.038 and 0.06 and methods by non-contiguous for BCS is -0.13, 0.09, 0.115, 0.04 and 0.02 obtained. Because of the low correlation between BCS and other economic factors, but by the mid and late lactation milk yield in a low to moderate correlation ,As a result of this negative correlation is due to a slight decrease in milk production in cattle ,As Considering the profits from improved health and reproduction of the next drop of milk should be considered. Keywords : Body Condition Score, Genetic and environmental correlations, Milk production traits, Random regression, Holstein cows