Abstract Pollination biology of Annona squamosa was investigated in the context of functional specialization and pollination syndrome. Hermaphroditic flower exhibited protogynous dichogamy as stigma became receptive a day before anther dehiscence. Flowers produce moderately high number (16,280 ± 324) of spherical and medium size (98.6 μm × 87.3 μm) pollen with pollen/ovule ratio of 120.6. Nitidulid beetles; Carpophilos domidiatus and Carpophilos hemipterous were identified as pollinators in terms of visitation frequency, pollination potential index score and pollination efficiency. However C. hemipterous was relatively effective pollinator than C. domidiatus. Floral traits and specific reward system of A. squamosa clearly exhibit obligate specialization by filtering only C. hemipterous and C. domidiatus as pollinators and thereby explicitly indicating canthrophilous pollination syndrome.