Compounds in the series Sm2Fe14-xCoxAl3 (x = 0, 1, 2, 3, 4 and 5) have been shown to be of the Th2Zn17 structure. The Curie temperature is found to increase monotonically from a critical temperature, T-c equal to 471 K for the x = 0 sample, to T-c = 681 K for the x= 5 sample. X-ray diffraction measurements of magnetic field oriented powders showed that all compounds exhibit a room temperature uniaxial anisotropy. Magnetization measurements show that the magnetic anisotropy of Sm2Fe14Al3 can be increased substantially by the substitution of even a small quantity of Co for Fe. Results are discussed in terms of possible applications of these compounds as particulate recording media.