Nine Holstein lactating cows, with an average live body weight of 550 ±50 kg, at1st to 3rd seasons of lactation, were selected and randomly assigned to three similar groups (three cows each). Cows were used in a lactation study for a total of 12 weeks (4-week prepartum to 8-weeks postpartum) to investigate the effect of feeding two levels of rumen protected choline (RPC) supplementation, at 40 or 50 grams RPC /cow /day, or with no supplement (control) on compare milk production parameters and performance of dairy cows.Results showed insignificant differences (P>0.05) among groups in the digestibility coefficients of DM, OM, CF, EE and NFE, and also in nutritive value as TDN %, while CP digestibility coefficient and nutritive value as DCP% in RPC groups were significantly (P0.05) differences were observed between the groups in their average daily DM and TDN intake, while results of DCP intake were significantly (P