Technical Abstract: Lupinus leucophyllus is one of many lupine species known to contain toxic and/or teratogenic alkaloids that can cause congenital birth defects. The concentrations of total alkaloids and the individual major alkaloids were measured in three different years from different plant parts over the phenological development of the plant. All of the alkaloids were found in the different plant tissues throughout the growing season, although their levels varied in the different tissues. Concentrations of the total alkaloids and the individual alkaloids varied on an annual basis and in their distribution in the different tissues. Anagyrine levels were highest in the floral tissue, lupanine and unknown F accumulated to the greatest level in the vegetative tissue, and 5,6-dehydrolupanine accumulated to the highest level in the stem. These alkaloids appear to be in a metabolically active state with the teratogenic alkaloid anagyrine accumulating to its highest level in the developing seed. The latter is thus the phenological stage posing the greatest danger to grazing livestock.