Vaccination is a feasible strategy for the control the haematophagous poultry red mite Dermanyssus gallinae. A cDNA library enriched for genes upregulated after feeding was created to identify potential vaccine antigens, based on their inferred function as digestive enzymes. A gene (Dg-CatD-1) encoding for a 383 amino acid protein (Dg-CatD-1) exhibited 53% identity (4.3E-101) to Cathepsin D lysosomal aspartyl proteinases. A second gene (Dg-CatL-1) encoding for a 341 aa protein (Dg-CatL-1) exhibited 37% identity (2.5E-48) to cathepsin L cysteine proteinases. IgY obtained from naturally infested hens failed to detect Dg-CatD-1 suggesting it is a concealed antigen. Conversely, Dg-CatL-1 proteins were detected by natural-infestation IgYs, indicting infested hens are exposed to Dg-CatL-1. Mites fed with anti-Dg-CatD-1 IgY demonstrated a statistically significantly higher mean mortality rate (0.23) than control (0.09); though the mean mortality rate in mites fed anti-Dg-CatL-1 IgY (0.14) was not statistically significantly different (P = 0.06) to that of the control. In a survival analysis, mites fed with anti-Dg-CatD-1 and anti-Dg-CatL-1 IgY had 4.42 and 2.13 times higher risks of dying compared with controls; both effects are formally statistically significant at the 5% level. Dg-CatD-1 and L-1 both have potential as vaccine antigens as part of a multi-component vaccine and have the potential to be improved using alternative expression systems.