The study aimed to report peacock mites (Acari: Tuckerellidae) on cocoa fruits (Theobroma cacao L.; Malvaceae) in the northeast Bragantina region, state of Pará, Brazil. Two mite species were identified, Tuckerella ornata, with 149 specimens, 32.89% on leaves and 67.11% on fruits, and Tuckerella knorri, with only two specimens on leaves. It was found that green fruits with T. ornata significantly reduced the size and weight of seeds. More attacked fruits, with more severe damage, showed deformations and thick cracks. Significant damage was noted in the Forastero cocoa seeds, visible to the naked eye, with light brown spots and a fine crack on the epidermis.