It is unfortunately true that many people in Tanzania are still suffering from malnutrition despite of the vast expenditure of time, money and effort in attempts to improve the nutritional status. Today, to eradicate malnutrition is, therefore, recognized as one of major aims to be urgently achieved in the national development plan in Tanzania. Thus it could be worthwhile to review the nutritional status and its influential factors in Tanzania in order to understand the entire problem correctly.Various clinical and dietary survey data clearly show that the nutritional status of Tanzanian people is generally considerably low as compared to that of those in developed countries and that the incidence of various types of malnutrition is high in the country. Among different nutritional disorders existing in Tanzania, Protein-Calorie Malnutrition (PCM) appears to be the most important disorder because of its wide distribution, its vulnerable group which is mainly children who are the future capital, and its complexity of causation.Influential factors on nutrition discussed in this paper are summerized as follows.From the demographic point of view, as commonly seen in developing countries, the rapid increase of population is a considerable problem especially in relation to the demand and supply of food. High dependency ratio in the population undoubtedly affects the nutritional status particularly of children under five years and, pregnant and lactating women owing to their low social status.With regard to dietary factors, it is noticed that Tanzanian diet is not necessarily less nutritive but insufficient in amount. It is, therefore, thought that the nutritional status could be substantially improved by simply increasing the daily food intake of individuals. The dietary improvement not only in quantity but also in quality, is, however, certainly desirable to improve the nutritional status particularly for those whose staple foods are banana and starchy roots.In connection with the population increase, the per capita food production of Tanzania tends to decline in recent years despite of the increase of gross food production. Taking this fact and population increase into consideration, it is obvious that paying more effort to increase the yield per unit area under cultivation of food crops is inevitable in the long run. In addition to raising the food production, the proper conservation of food currently produced is considered to be of great help to increase the amount of food available resulting better nutritional status. Concerning the food production, it should be added that the land tenure system of Tanzania which enable people to obtain farming land readily is acting an important role to increase the food availability of individuals.From the socio-economical point of view, though there is not a remarkable gap between the rich and the poor, the presence of unequal intra-family distribution of income tends to create the malnourishment of dependent group in a family. It is also noticed that with economic development people do not always improve their nutrition. Food habit based on long established cultural patterns is often limiting the food availability of a certain group of the population in Tanzania. As a matter of fact, that socio-economic factors, particularly poverty and ignorance as primary causes of malnutrition, underlie most other causal factors makes the improvement of nutritional status difficult.In view of environmental factors, it is observed that inadequate water supply in quality and quantity is highly related to lowering the nutritional status. The availability of water in Tanzania is actually one of the most important factors to limit agricultural production as well as human life. It is noticed that as a result of “villagisation”, the social environment in rural area has been considerably improved particularly in terms of the access to medical and educational facilities. The