The objective of this study was to determine of nutritional value, in vitro cytotoxicity, and oxidative stress parameters in cells of selected insect species (Tenebrio molitor and Zophobas morio) after 30 days of Styrofoam consumption. Furthermore, part of our research is also a consumer survey on the willingness to eat insects fed with Styrofoam (EPS 80). Mealworms fed with Styrofoam were determined to have higher protein (48.66 ± 0.92%) and ash content (4.81 ± 0.22%) with reduced fat (24.05 ± 0.55%) and carbohydrate content (2.95 ± 0.15%) than insects with a conventional diet (48.66 ± 0.92, 2.82 ± 0.12, 43.74 ± 0.77, and 4.78 ± 0.18, respectively) while in the case of superworms, no significant difference in nutrient composition was observed. Moreover, Styrofoam has no influence on the health status of gut cells in examined insects. Additionally, in studied concentrations of insects extracts standardized for protein replacement of the traditional insect diet with polystyrene foam did not increase the cytotoxic properties.