Title of the paper: <b>Estimation of genetic parameters for test day results of milk performance in East Friesian milk sheep using Bayesian methods for longitudinal data</b><br> The objectives of this study were to estimate genetic parameters of milk performance traits in East Friesian milk sheep by using test day models with random regresssion. The analysis was based on 7545 test day records of 918 East Friesian milk sheep with 1380 lactation records. The data were provided by the sheep breeding organizations of Lower-Saxony, Westphalia, and Bavaria. The milk recordings were collected in the years 1992 to 2000. The average values of the heritability estimates by using random regression models were for the milk yield h<sup>2</sup> = 0.25 ± 0.03, for the fat content h<sup>2</sup> = 0.46 ± 0.09, and for the protein content h<sup>2</sup> = 0.63 ± 0.12. The range of heritability estimates in dependence of the days in milk was for milk yield h<sup>2</sup> = 0.03 to 0.70, for fat content h<sup>2</sup> = 0.30 to 0.70, and for protein content h<sup>2</sup> = 0.44 to 0.92.