Images of Phobos and Deimos acquired by the Viking orbiter television system have been used to determine the photometric functions of the Martian moons. Data covering wavelengths from 445 nm to 593 nm and solar phase angles between 0.5¿ and 122¿ were used. Normal reflectances of 0.066¿ 0.006 for Phobos and 0.069¿0.006 for Deimos were determined. No variations in either photometric function or average normal albedo were observed over the wavelength range studied. The photometric functions demonstrate that the surfaces of Phobos and Deimos are intricate in texture and exhibit brightness surges near opposition that are more pronounced than that of the moon.