Malnutrition is a condition that results from nutrient deficiency or overconsumption/ It is a condition that results from eating diets in which one or more nutrients are either not enough or are too much such that the diet causes health problems. It can be overnutrition or undernutrition. Disease-related malnutrition is the type of malnutrition that is triggered by illness or disease. Certain diseases and their treatments have a negative impact on nutrition. Disease-related malnutrition is a condition characterized by inadequate intake of energy, protein and /or micronutrient as a result of diverse number of diseases and their treatments. It is the primary reason for malnutrition in developed countries especially in the elderly since many of the diseases triggering malnutrition are related to age. It can affect individuals at any life stage including infants and children however, the prevalence is significantly higher in the elderly. The world prevalence of malnutrition is between 40-70%. Economic cost is referred to how much it cost to deal with consequences of problem. It includes opportunity cost and accounting cost. Economic cost of disease related malnutrition is both forgone opportunities and money it cost to deal with the consequences of disease-related malnutrition. The causes of disease-related malnutrition are of three aspects which are interlinked: increased nutritional requirement, reduced nutritional intake, and increased nutritional losses. Consequences can be physical, physiological and/or psychological. Economic cost of disease-related malnutrition is very high because is associated with an increase in morbidity and mortality, augmenting resources use and associated cost. Economic cost can be the additional health care cost, negative impact on social and economic development of countries, lost of income due to illness, reduced school performance and later earnings due to cognitive impairment and death. Pathways from malnutrition to economic cost are mortality, ill health, impaired physical growth and impaired cognitive development. In conclusion, malnutrition keeps people from reaching their potentials and disease-related malnutrition has a very high economic cost as malnourished adults are less able to work, contribute to local economies and provide care for their families.