Irrigated potatoes were grown on a sandy soil which ranged in available P and K from 53 to 308 and 45 to 319 kg/ha, respectively. The levels of soil P and K as measured by soil test (Bray #1) were compared with yield, specific gravity of the tubers, and P and K tissue concentrations. The response of the potato crop was correlated to soil K but not to soil P. Yields increased with increasing soil K from 45 to 196 kg/ha in the surface sample and leveled off there after. The fact that the levels of subsoil K increased with increasing surface soil K may have had somewhat of an effect on the leveling off of potato yields at 196 kg/ha of K. The lack of a yield response to soil P was associated with adequate available soil P at the lowest soil test levels.