Nitrogen loss by leaching can potentially be reduced by using controlled-release fertilizers in place of soluble formulations. A 1-year field study on citrus was used to estimate N release patterns of four controlled-release fertilizers and a water-soluble material. Similar studies were conducted in central (Lake Alfred) and southwest (Immokalee) Florida simultaneously. Mesh bags (13 x 13 cm) containing 3.5 g of actual N from each source were placed on the soil surface within the irrigated zone under the tree canopy to estimate N release rates from the selected fertilizers. The water-soluble mixture was applied three times during the year, while controlled-release materials [Citriblen® (15% N), Osmocote® Type A (19% N), Osmocote® Type B (17% N), and Poly-S® (37% N)] were applied once. After 365 days in the field, the percentages of N released were 99, 95, 93 and 88% of the total N applied as Osmocote A, Citriblen, Poly-S, and Osmocote B, respectively at Immokalee, and 97, 90, 81, and 77% of the total N applied as Osmocote A, Citriblen, Poly-S, and Osmocote B, respectively at Lake Alfred. The entire N from the water-soluble fertilizer was released after a single rainfall occurred. The N release patterns from controlled-release fertilizers varied depending on the type of material, and it appeared that environmental conditions were more favorable for N release at Immokalee than at Lake Alfred.