This research took place in Uraba, Antioquia, in the CENIBANANO-AUGURA experimental field, where a research program on nutrition and fertilization in bananas is carried out. This crop requires high amounts of nitrogen for production, so it is indispensable to evaluate the impact of these applications on the carbon-nitrogen ratio (C/N ratio) in soil. Published literature is scarce for this problem. This research evaluated the C/N ratio in areas with fertilizer applications and nutrient uptake, along with the interaction with production in a banana crop of the AAA group giant Cavendish subgroup, Williams clone, sixth generation in two production cycles. A randomized complete block design was used with five treatments that consisted of differential doses of nitrogen (161, 321.8, and 483 kg ha-1), and an omission and absolute control distributed in four replicates. The treatments with nitrogen doses generated statistical differences for the interactions between the two study zones for the percentages of carbon and total soil nitrogen and C/N ratios; the highest values were found in the fertilization zone during the first production cycle (2.47% C, 0.33% N, and 7.7 C/N ratio). The treatment with 483 kg ha-1 of N obtained the greatest increases in the values for these variables that are attributed to the highest dose of nitrogen and the residual acidity of urea that was able to release non-free carbon from the soil. For this reason, the correlation analysis for the C/N ratio and production was significant for the study areas (absorption and fertilization), inferring that higher C/N ratio values tend to increase production.