To assess loss of the minerals; Na, K, P, Ca, Mg, Fe, Zn, Mn, Cu during cooking, their contents in food were determined before and after cooking. The results obtained were as follows. 1) The mineral contents in cooked food were on average about 75% of those in raw or uncooked food. 2) Among various cooking methods, loss of minerals was largest for squeezing after boiling and for soaking in water after thin slicing, followed by parching, frying and stewing. 3) Cooking losses were almost the same for both large-scale and home cooking. 4) Measures for preventing cooking loss are (1) eating with soup after boiling, (2) addition of a small amount of salt (about 1% NaCl) when boiling, (3) avoidance of excessive boiling, and (4) selection of a cooking method causing less mineral loss (stewing, frying or parching).