Abamectin is one of the avermectins that are known for their efficacy in controlling the mites and ticks. Understanding the biochemical effects of abamectin on ticks is crucial for identifying their possible mode of action and optimizing its application to manage tick populations. This study aimed to investigate the biochemical effects of abamectin on Argas (Persicargas) arboreus eggs during embryogenesis. The topical application of 5 ppm abamectin (LC₅₀) on newly deposited Argas (P.) arboreus eggs quantitively changed the total protein and DNA content, causing fluctuation and decrease of their concentration, respectively, during embryogenesis. Also, such treatment disturbed the normal electrophoretic patterns of the separated protein fractions of the developing embryos on 0, 3, 5, and 8 days post-treatment and post-oviposition (POP). Comparison among the protein fractions patterns (molecular weight, number, percent of the amount, and appearance or disappearance of bands) in each of the untreated controls and abamectin-treated eggs, and between them showed noticeable changes of the patterns during normal embryogenesis, and disturbance from the normal as a result of such treatment. The changes and disturbances of the total protein concentration and fractions were most prominent on 5-8 days post-treatment and POP during the periods of gastrulation and organogenesis. These findings demonstrate the significant impact of abamectin on biochemical components and highlight the disruptions caused by the abamectin treatment during embryonic development in A. (P.) arboreus eggs.