Burnham describes Albireo as one of the most beautiful double stars in the sky, consisting of a bright "golden yellow" primary with a blue or "sapphire" companion.
The brighter star Albireo A is a K3II bright giant. This type of star is cooler than the sun, with an effective temperature of approximately 4100 K. It is probably about 20 times larger in radius than the sun and 100 times as luminous.
The The Bright Star Catalog suggests additional components at separations from A well under one sec of arc. The Hipparcos Catalog lists a C component at a separation of 0.389 seconds of arc (46 AU separation at the distance of the star). The C component is some 2 magnitudes dimmer than A.