The research was conducted on the family farm "Aščić" from Velika Peratovica in the area of Bilogora. Sheep's body measures (withers height, body length, chest width, chest depth, chest circumference and shin bone circumference) was carried out with the help of Lydtin's rod and measuring tape, and the determination of body weight was done using a livestock balance. From body measurements was calculated indices of physical development of sheep. Body measurements and weight were taken from 39 sheep divided into two groups, first group of 14 sheep to 3 lactation and the second group of 25 sheep in 4 and higher lactations. Sheep all the time stay outdoors in the open pasture without extra feeding with hay or feed mixture. Sheep in the present research had a lower body mass, chest circumference, chest depth, chest width and shin bone circumference, as well as higher withers height and similar body length compared to the preferred measures listed in the Sheep Breeding Program in the Republic of Croatia. The body weight of the sheep in the present research is lower for 26.16 %. The increase of the number of lactation shows a tendency of the growth of all investigated body measurements of sheep, but without statistically significant differences (P>0.05). Average body condition score of sheep during lactation in present research is at the lower limit 2.677of preferred values. Pearson's correlation between individual phenotypic traits was determined by the strongest and significantly positive correlation (P<0.05) for chest width (0.81). Regression analysis established equations for prediction the body weight of sheep as dependent variables and determined determination coefficients. The highest coefficient of determination was determined from the chest width variable. The maximum value of the coefficient of determination 0.86 was determined when all the variables (body measures) were included in the equation. Based on the colinearity diagnostic, the best prediction equation for predicting the body weight from body measurements is by including the chest width Y = -7.303 + 2.955 x C.W. Chest width is the best predictor for the estimation of body weight and this alone contributed 65 % variation in the body weight of adult Travnik sheep.