In processed tomatoes production of ripe fruit was significantly affected by irrigation schedules. Within the range of the test treatments, the longer the period between irrigations, the higher the percentage of ripe fruit and of solids. However, there was a highly significant reduction in yield and an increase in the amount of sunburn as the irrigation interval increased from 10 to 15 and 20 days. The 10-day irrigation cycle appeared to be the most suitable practice, yielding the highest tomato tonnage per acre, and consistent with the evapo transpiration and the gypsum block records. Longer irrigation frequencies depressed yield, stressed the tomato plants, and increased the percentage of sunburned fruits. Pre-irrigation is a very important practice in the production of tomatoes on the west side of the San Joaquin Valley.