Abstract Silencing Amblyomma americanum insulin‐like growth factor binding protein‐related protein 1 ( Aam IGFBP‐rP1) mRNA prevented ticks from feeding to repletion. In this study, we used recombinant (r) Aam IGFBP‐rP1 in a series of assays to obtain further insight into the role(s) of this protein in tick feeding regulation. Our results suggest that Aam IGFBP‐1 is an antigenic protein that is apparently exclusively expressed in salivary glands. We found that both males and females secrete Aam IGFBP‐rP1 into the host during feeding and confirmed that female ticks secrete this protein from within 24–48 h after attachment. Our data suggest that native Aam IGFBP‐rP1 is a functional insulin binding protein in that both yeast‐ and insect cell‐expressed r Aam IGFBP‐rP1 bound insulin, but not insulin‐like growth factors. When subjected to anti‐blood clotting and platelet aggregation assays, r Aam IGFBP‐rP1 did not have any effect. Unlike human IGFBP‐rP1, which is controlled by trypsinization, r Aam IGFBP‐rP1 is resistant to digestion, suggesting that the tick protein may not be under mammalian host control at the tick feeding site. The majority of tick‐borne pathogens are transmitted 48 h after the tick has attached. Thus, the demonstrated antigenicity and secretion into the host within 24–48 h of the tick starting to feed makes Aam IGFBP‐rP1 an attractive target for antitick vaccine development.