Cross-polar radiation of a novel dual-band coaxial hybrid-mode feed horn with partial dielectric loading for single and dual reflector antennas has been investigated. In comparison to dual-band corrugated horns this horn has higher crosspolar level, but provides larger band separation (e.g., 6.6:1 in the paper) and rather good electrical performances over a wide frequency range (20% and more) within each operational frequency band. Furthermore, the main concept of the coaxial feed system can be easily extended for multi-band cost-effective applications.