To investigate the effects of different type of dietary fat on survival metabolism of fasting rats, one group rats (FO) were fasted, another one group rats (BM) were fed normal diet and the others were fed only one of the following fat diets: beef tallow (FT), corn oil (FC), and perilla oil (FP) of 11.4g/kg respectively. Most FO group rats survived for 6 days and large part of the only-fat-diet groups rats survived for 16 days. Body weights of all rats in fasting and only-fat-groups, measured just one day prior to death owing to fasting or caloric malnutrition, decreased by 24.5%~25% only-fat to fasting rat somewhat extended the survival time but the specific properties of dietary fat types had no remarkably differential effect on survival time and body weight gain rate. The features of liver and kidney weight gain rate of all rats in fasting and only-fat-diet groups were similar to those of body weight gain rate. In FO groups blood levels of total-cholesterol, triglyceride, and glucose markedly reduced whereas GPT activities and BUN levels considerably increased as compared to BM group. However the types of dietary fat perse did not affect blood total cholesterol, triglyceride, glucose, BUN levels, and GPT activities in early stage of fasting in FC and FP group. GPT activities in rats of FP group just prior to death of starvation seemed to be affected by the dietary fat types. The results showed that only-fat-feeding to fasting rats somewhat extended survival time but the types of dietary fat had no remarkably differential effect on survival time and metabolism of fasting rats.