This study was performed to determine the histologic structure of the uropygial gland in an osprey. The gland was composed of two elongated lobes which were enclosed in a capsule of connective tissue. Each lobe of the gland had a large central cavity with one excretory duct. The secretory tubules consisted of four cell types: basal, intermediate, secretory, and degenerative. The intermediate cells in the osprey were few in number and did not form a layer, while secretory and degenerative cells consist of 2-3 strata, indicating a high level of lipogenesis. The membranes and peripheral cytoplasm of degenerative cells located in the base of the lobes revealed calcium (Ca2+) deposition and an intense acidophilic reaction.