In 2007, the Japan Atherosclerosis Society published the Guidelines for prevention of atherosclerotic cardiovascular diseases. However, the guidelines have several flaws with regard to the cutoff level of serum low-density lipoprotein cholesterol (LDL-C). First, LDL-C level is used instead of serum total cholesterol (TC) level in the guidelines. In this case, they must show at least some basic data on the relationship between LDL-C level and mortality or morbidity from coronary heart disease (CHD). Second, it was recommended that the LDL-C level be below 140 mg/dL or 3.6 mmol/L (corresponding to a TC level of 220 mg/dL or 5.7 mmol/L, respectively). These levels are unreasonable considering that the TC levels of 240-260 mg/dL are optimal in terms of all-cause mortality for the Japanese population. Third, although there are big differences in mortality and morbidity from CHD between sexes, they discussed the matter without considering these differences. Last but not least, the conflict of interest of the editors of the guidelines has never been disclosed. The Japanese population has a lower CHD mortality and incidence than populations from other industrialized countries despite an increase in serum TC level in the former. In populations with a markedly lower coronary mortality or morbidity such as the Japanese population, it is still important to determine the optimal cutoff level of LDL-C to prevent the development of CHD and other atherosclerotic diseases.