SUMMARY— Among the advantages of processing tomatoes in the field, compared with processing solely at a cannery, are increased yield and reduced waste. Mechanically harvested tomatoes were processed at 500 lb/hr through a mobile field unit within 6 hr after harvest during the 1969 season. Processing within 6 hr from harvest prevented a loss of about 9.5% of the ripe tomatoes that occurred when processing was delayed 24 hr. An increase of 4.3% in solids recovery was obtained by acid treatment of the hot macerate, bringing the total increase to 13.8% for field processing. Either the single strength or concentrated material is suitable for bulk transport to a cannery for storage, additional concentration, or immediate formulation into sauces, catsup and other tomato products.