Hyperbaric treatment consists of exposing fruit or vegetable to compressed air in a range lower than 10 atm. Unlike heat or UV processing, where temperature or radiation gradients are established, pressure treatment offers a very rapid establishment of homogeneous conditions as they act instantaneously and uniformly around each single produce or throughout an entire mass of food, independently of its size, shape or composition. A hyperbaric respirometer was designed, built and tested to explore the possibility of using hyperbaric treatment on postharvest commodity. It consisted of an air tight vessel that could be pressurized from 1 to 7 atm and instrumented to automatically monitor gas concentration along time using computer controlled valves, flow meter and CO(2) gas analyzer. Calibration of the system and hyperbaric treatments were performed on tomato fruit to evaluate the performance of the respirometer. Results showed that respiration rate was inversely proportional to pressure application. (C) 2011 Elsevier Ltd. All rights reserved.