Tomato cannery wastes, although high in moisture, contain a good proportion of protein (20–22%). An alkaloid, tomatine, was found in quantities up to 0.5% in leaves to practically nothing in the fully ripe tomatoes. The vines and stems had a protein content of 14–21% dry weight basis. A process for totally utilizing tomato cannery waste was developed where the waste was chopped, wet-milled, alkalized and the presscake containing two-thirds of the solids, 10% protein, could be used as cattle feed and one-third of the solids, ≤60% protein, was precipitated by acidification as a tomato protein concentrate (TPC). The bulk of the protein (78%) is precipitated at pH 4.8,14% at pH 4.0, and 8% at 3.5 pH. The concentrate can be extracted with acetone to form ≤85% protein isolate plus a tomato flavor and pigment residue.