The present state and determining the production problems and also presenting the guidance for quantitative and qualitative improvements of almond, walnut, pistachio and hazelnut, a research was conducted from 2004 to 2005. Firstly, using the statistics published by Ministry of Agricultural Jihad, 19 provinces of important fruit producing and a few cities in each province were selected. Then, using a questionnaire, all aspects of information from these centers were collected. Provinces selected were east Azarbayejan, west Azarbayejan, Ardebil, Isfahan, Tehran, Chaharmahal Bakhtiari, Razavi Khorasan, north Khorasan, south Khorasan, Fars, Kurdestan, Kerman, Kermanshah, Kohkiluieh and Boyerahmad, Lorestan, Mazandaran,  Markazi, Hamedan and Yazd. The results showed that in spite of some problems in cultivation of these fruits, especially early spring frost which damages early fruiting species, like almond, walnut and pistachio, average yields per hectare of these species are not less than average yields of important countries in Europe and in some cases they are higher. In the year of experiment, according to FAO report, average yields per hectare of almond were 0.84 in Iran, 4.25 in France, 1.84 in Turkey and 0.33 tons in Spain. Similarly, average yields per hectare of walnut were 2.31 in Iran, 1.66 in France, 1.85 in Turkey and 3.85 tons in Spain. Average yields per hectare of 0.63 and 1.13 tons for hazelnut and pistachio in Iran, respectively, 2.49 tons in France for hazelnut, 0.79 tons in Turkey for pistachio, and 1.00 tons in Spain for hazelnut were reported. These achievements are under situations that a number of reducing factors are present in Iran. The results of this investigation showed that in the years of the study, the production problems include lack of covering insurance or guaranteed market, low knowledge of fruit producers on orchard management particularly pruning  irrigation, spraying against insects and deseases, fertilizing etc. It can be concluded that in Iran the potentials for increasing the yields of these crops for internal consumptions and export are available.