Incorporating legumes such as lupins into crop rotations enhances system sustainability by supporting ecosystem services and supplying plant based protein alternatives in human nutrition. Nevertheless, growing legumes is frequently associated with a high risk for farmers due to volatile year-to-year crop performance. Furthermore, overall accessibility of arable land is decreasing. Mixed cropping could buffer risks, increase land-use efficiency and improve crop stands by diversification, resulting in high-quality yields. The aim of this study is to investigate pre- and postharvest crop performance of lupin-cereal mixtures and their pure stands. Two-year field experiments were conducted in 2024 and 2025. All cropping systems included two narrow-leafed lupin varieties and consisted of pure lupin stands, lupin mixtures with oats or wheat, and pure respective cereal stands fertilized according to Swiss national standards or without fertilization. Depending on the companion crop and variety, mixed cropping reduced weed biomass substantially under high weed pressure compared to pure stands. In cereals cereal leaf beetles and aphids dominated in 2024 and 2025, respectively, while in 2025, the aphid pressure was also high in lupins. Under high pressure, the number of aphid colonies in lupins in mixed stands was less than 50% of that in pure stands. The land equivalent ratio (LER) values were below one. The protein yield and protein content could be increased depending on year and pure crop stand performance. This study demonstrates the overall performance and risk-buffer-effect of lupin-cereal mixed cropping systems, supporting decision making for farmers interested in cultivating lupins.