Crystal structure and magnetic properties of Ce
xPr
1-xCo
5compounds (

) have been investigated. Only the hexagonal structure of the CaCu
5type exists in the whole range of this system. Lattice parameters were precisely determined by extrapolating

versus the a and c axes plots using computer calculations. The a axis decreases and the c axis slightly increases linearly as the cerium content increases. This dependency could be explained by the difference of the atomic radius of the two rare-earth elements involved. Using the obtained values of lattice parameters, the radius of cobalt and the first and second nearest neighbor distances between cobalt and rare earth sites were graphically determined. Saturation magnetization and crystal anisotropy constant were determined from the magnetization curves by a vibrating sample magnetometer. The Sucksmith-Thompson plot was adopted for determining the anisotropy constant with computer analysis. The anisotropy constant K
1shows convex change with increasing cerium and shows a maximum value of 6.2 erg/cm
3at x = 0.2.