Abstract: The objective of this study was the development and the evaluation of press-coated tablets for the modified release of nonprotein nitrogen in the rumen based on: urea, ammonium phosphate monobasic and ammonium phosphate dibasic, in order to be used as a protein supplement in ruminants. The release profiles, showed that tablets with urea had a better control of release although were faster than the other sources. The 80% of total urea was released in 31 h whereas, ammonium phosphate monobasic and dibasic released only 27% at the same time in the dissolutor with distilled water. Testing the press-coated tablets with ruminal fluid presented similar performance, with a half time of release of 26.45 h urea, 41.25 h ammonium phosphate monobasic and 25.02 ammonium phosphate dibasic. The press-coated tablets are potential technology to provide nonprotein nitrogen for prolonged time to ruminal microbes and the ruminant.