This paper report and discuss results referring to a field trial set up to study irrigation and fertilization problems of old coffee plantations. The seven year study, started 1953, was conducted at a representative well kept coffee grove of Bourbon variety, about 40 years old, located in a typical purple soil formation of the Ribeirão Preto Experiment Station, considered to be representative of all the region. Eight randomized blocks were used with a 2x2x2 factorial for the small treatments in each block, the following treatments being compared: complete chemical fertilizer in two dosages, with and without organic manure, with and without green manure as annual intercrop. The irrigation treatments included in the first two years application of 1 and 2 inches of water, every 3 weeks, starting July, 2 inches starting August and no irrigation. The remaining 5 years the treatments compared were simply with irrigation and no irrigation. Irrigation application time was determined by soil moisture depletion, when about 55 milimeters were consumed from the 0-80 em soil layer. The results have shown substantial increase in production during dry years, however its significance is diminished by the biennial bearing effect occurring in coffee plants. During wet years irrigation may even diminish production, when heavy rains soon follow the application of water. Use of green manure as annual intercrop was shown not to increase production, the same occurring with the use of organic manure in the dosage of about 12 kg every year per coffee tree (which means a group of 3-5 trees originally planted in the same hole). When production of the treated plots were compared with the untreated border plot trees, it was shown an increase of about 24% due to the effect of chemical fertilizer alone. However, the present economical situation in Brasil does not favor the use of fertilizers on a profit basis. Considering the success obtained in forming new coffee plantation in places where there was before old coffee plantation, a practice which is growing in importance, it would be out dated to recommend expenditures do try to improve old coffee plantation of the type reported. The irrigation equipment used for the experiment and part of the laboratory equipment needed was acquired through a donation of the Rockefeller Foundation, which has cooperated with us whenever needed and to which we owe due recognition.