Determinations of fruit setting were made in a fertilizer trial that is being carried out at the Estação Experimental de Ribeirão Prêto. This experiment is a factorial 2(4) with four replications, the basic treatments being 10 kg of "estêrco" (e), 0.2 kg of ammonium sulphate (n), 0.2 kg of bone meal (p) and 0.1 kg of potassium chloride (k). Fruits were counted in November of 1953 and 1954, soon after flowering, and also in February of the following years, when the fruits were already well developed. By fruit setting it is meant the ratio between fruit numbers in November and February, although counting was made at 15-day intervals between these two dates. In 1953/54 the percentage of fruit setting was determined for one plant in each of the four replications of treatments e, en, ep and ek. One plant in each replication of treatments np, en, enk and enpk was studied in 1954/55. For each plant in both seasons, six flowering branches were used, two at the higher part of the coffee plant, two at the base and two in intermediate positions. From the results obtained it is concluded that chemical fertilizers may contribute significantly to increase the percentage of fruit setting. Together with "estêrco" (stable manure), phosphorus showed a 3.5 per cent increase over "estêrco" alone. Comparing treatments with and without potash an increase of 8.1 per cent was found for plots receiving this fertilizer in 1954/55. It is also concluded that significant differences were observed in fruit setting at different levels of the plant, in favor of the higher branches. Fruit setting showed no correlation with total yield of ripened fruits.