A feeding trial was conducted to study the effect of urea on the milk secretion and palatability of ration in place of soybeanoilmeal as a partial substitute for protein in the regular ration of lactating dairy cows. Seven lactating dairy cows that had almost similar milk production, lactation stage, general feeding and passed their peak in milk production entered the experiment from Nov. 5 1957 to Dec. 14 1957. The experiment consisted of each a 10 days of preliminary period, control ration period, experimental period and control ration period totaling 40 days. Morrison`s feeding standards were adapted. Concentrate ratio is given in table 1. Roughage ratio consisted of 21 Kgs of corn ensilage, 4.5 Kgs of natural grass hay were supplied both to control and experiment periods. Inorganic matters consisted of 1% of salt and 2% of shill meal, of total amounts of concentrates. Urea was a products of Nitrogen Division Alied Chemical and Dye Corporation, Ohio U.S.A. And its 42.0% of minimum nitrogen amounts was equivalent to 262% of crude protein. The urea was composed of 91% of urea, 4% of wheat bran and others, and 5% of lime. $lt;Table 1 생략$gt; Two to three times of hand milking and three diets daily were practiced and clean water was available at all times except experiment period in which it was supplied 90 minutes after each diet. The regular ration was in general somewhat more palatable than the ration which contained urea. This was particularly noticeable during the earlier stages of the work; as the cows became accustomed to the urea the difference in flavor of the regular ration became much less and finally disappeared almost entirely as approach the end of the experiment period. Feeds supplied were almost completely eaten up in both control ration and experiment periods and no unfavorable influences were observed. Statistical analysis of the detailed data by means of the T test of Significant Difference showed that none of the differences in average milk yeild were significant but $quot;null hypothesis$quot; was acceptable. $lt;Table 2 생략$gt; $lt;Table 3 생략$gt; Only last 4 days in experiment and control ration period - 7, 8, 9, 10 - were taken in consideration in order to avoid any influence owing to feed sifting, Results of experiment showed that, with recognition of its limitations, urea will undoubtedly find a place in the feed as a substitute of protein, especially in such times of protein shortage as we are now experiencing without any undue influence on body structure, palatability and milk secretion.