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  Introduction: Several definitions of poverty have been presented with different natures in respect to methodology. Moreover, various methods of measuring the minimum livelihood have done. One of the specific definitions among them is the relative poverty line which refers to disability of households to provide a specific level of life standards, seems necessary and favorable.

  Method: In this research linear expenditure system for evaluating minimum livelihood was used and the portion of Iranian indigent families examined.

  Findings: Resulted coefficients of marginal tendency towards expenditure for commodity groups indicate that this coefficient for commodity groups of Houses and Foods is greater than other commodity groups. It means existing poverty in the society, therefore calculated poverty line for 2010 is equal to 3506960.3 Rails.

  Results : The results show that the commodity group of recreation belongs to normal and luxury goods while the other belongs to normal and necessary goods. The results were concluded from the calculation of poverty line which indicates an increase in annual minimum livelihood of families. To be mentioned the estimated numbers based on this method can be greater with respect to a two- digit inflation rate for the economy of Iran and surprising policies of Central Bank and government. Accordingly, we suggest adopting vulnerable household's protection policies and distributive aims in order to decrease the poverty line and to improve the household’s welfare.

  Classification : JEL: C42, R 58.

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introduction:Nutrition and consuming food are very important  in the planning of the household budget . The analysis of the allocation of household income to goods and services is of interest to economists and politicians, and estimating the demand for goods and services is important in identifying future preferences and needs. Recognizing household consumption priorities will help plan to increase  their welfare. Therefore, the present research  aims to study the food basket in urban areas of Iran.
Method: Using the seemingly  unrelated regression (SUR) and maximum likelihood (FILM) estimation method, the  almost ideal demand systems (AIDS) and linear expenditures (LES) for urban households, as well as the testing of symmetry and homogeneity hypotheses using the Ivyz software Eviews) were estimated.  At the end of the incremental, cross, and income separately for each The demand equations are calculated.
Findings: The homogeneity hypothesis for all three groups of bread and cereals, protein and fruits and vegetables is accepted in the food demand function of AIDS, but in the LES demand function, the homogeneity hypothesis is rejected for the fruits and vegetables group, and in the consumption of this group housholds have monetary illusion.   According to the results of the calculation of elasticity, in the food demand AIDS function, the group of bread and cereals are essential commodities, protein, fruits and vegetables, and other groups are considered to be luxury and for the LES food demand function, all commodities are essential.
Discussion: According to the comparison of the results of two demand models, the bread and cereal group in both systems are considered as essential commodity and as a result, they have more effects on welfare changes of households. Also, households do not have monetary illusions for the bread and grain group and are sensitive to real income. Given these results, when considering  policy making, we should pay particular attention to the bread and cereal group as the essential commodities of the household. The protein and vegetables group for the household is considered a luxury commodity. As the price of these groups rises, the demand for them decreases . In the event of an increase in household income, they will buy this group of goods.