The effect of cooking(boiling, steaming and baking) and drying on the cholesterol content and formation of oxidized cholesterols and acid value in squid(Japanese flying squid, Todarodes pacificus) was studied. Cholesterol content of live squid meat varied with the portion sampled. The data from spectophotometric assay ranged from 263.2 mg/100g(mantle) to 315.8 mg/100g(tentacle). The cholesterol levels found for squid samples analyzed by gas chromatography(GC) were lower by 7% of total cholesterol for live squid meat and 24% for processed meat than those results by spectrophotometric assay. Cooking resulted some decrease in the initial total cholesterol content of raw meat from 10%(boiling for 5 min.) to 25%(steaming for 5 min.). The amounts of cholesterol remaining after baking were 68% for microwave oven samples and 64% for convection oven samples. Drying of raw tissue caused the greater reduction in cholesterol content than cooking but brought about no significant difference in samples stored for 6 weeks at $4^{circ}C;and;20^{circ}C$. Raw squid meats contained essentially no oxidized cholesterols, while the 22-hydroxychoesterol was detected in frozen meats. The additional oxidized cholesterols as cholestane-triol was indentified with 22-hydroxycholesterol in cooked samples. Sun dried meat stored at $4^{circ}C;and;20^{circ}C$ for 6 weeks had the three kinds of oxidized cholesterols such as 22-hydroxycholesterol, cholesta-3,5-dien-7-one and cholestane-triol. For the boiled and steamed squids, 10% higher acid value and 5% higher acid value respectively were observed but oven cooked samples resulted in a 50% higher acid value than raw samples. Squids had a 45% higher acid value than raw one during sundrying and presrevation at $20^{circ}C$ but there was not a severe difference of acid value between $4^{circ}C;and;20^{circ}C$ stored samples.