A method for the determination of proteins in feeds, utilizing the Technicon® BD-20 block digestor, has been developed. Twenty feed samples are weighed directly into the 250 ml tubes and digested for 35 min after clearing. The temperature of the solution during the digestion and the uniformity of temperature between various holes in the block were determined. The effect of air currents over the tubes was also studied. Six replicate determinations on cottonseed meal, blood meal, soybean meal, tryptophan, and 2 feed samples are reported and compared to results on the same sample analyzed by the official final action Kjeldahl method; good agreement was shown between the methods. The accuracy of the block digestor was confirmed by analyzing 40 routine feed samples by both the block digestor and Kjeldahl methods; results did not show a significant difference when compared by Student's t-test at the 5% level.