Cover crops are beneficial to agroecosystems because they decrease soil erosion and nutrient loss while increasing within field vegetational diversity. Greater vegetational diversity within cropping systems can positively affect beneficial arthropod communities. We hypothesized that increasing the vegetational diversity within annually rotated corn and soybean with the addition of a rye cover crop would positively affect the beneficial ground and canopydwelling communities compared to rotated corn and soybean grown without a cover crop. From 2011 through 2013, arthropod communities were measured at two locations in Iowa four times throughout each growing season. Pitfall traps were used to sample ground-dwelling arthropods within corn and soybean plots and sweep nets were used to measure the beneficial arthropods in soybean canopies. Beneficial arthropods captured were identified to order and family level taxonomic units. In both corn and soybean, community composition and total community activity-density and abundance did not differ between plots that included the rye cover crop and plots without the rye cover crop. Most taxa did not significantly respond to the presence of the rye cover crop when analyzed individually, with the exceptions of Carabidae and Gryllidae sampled from soybean pitfall traps. Activity-density of Carabidae was significantly greater in soybean plots that included a rye cover crop, while activity-density of Gryllidae was significantly reduced in plots with the rye cover crop. Although a rye cover crop may be agronomically beneficial, there may be only limited effects on beneficial arthropods when added within an annual rotation of corn and soybean.