The phase diagram of the La-Co-Ni (La 32.2 wt%) ternary system at room temperature has been determined by X-ray powder method and metallographic examination.The isothermal section at room temperature was found to consist of four single-phase regions: α,β, LaCo13 and LaCo5xNi5-5x; five two-phase regions: α+β, α+LaCo13, β+LaCo13, β+LaCo5xNi5-5x and LaCo13+LaCo5xNi5-5x; two three-phase regions : α + β + LaCo13 and β+LaCo13+LaCo5xNi5-5x. No new phase has been observed in this range. X-ray analysis showed that the maximum solubility of La in β is about 9 wt%.