Persian literature has a brilliant record. However, in the old Persian poetry, children's and young adult poetry has no significant status. In fact, there is not much which can be attributed to children and young adults from the old Persian poetry. likewise, in other countries children's literature does not have a long history and is commonly regarded to have emerged around 17th century. Among Iran's literature, books such as Qaboos Nameh written by Qaboos Ebn Voshmgir for his sun Gilan Shah, some of the stories of Kelile and Dimne, some of the Nizami's poetry, and Mouse and Cat by Ubayd Zakani can be counted as some of the early instances of children's literature. However, no writerr or poet is introduced particularly as a children's writer or poet. During the constitutional era, under the influence of European literature, there have been poets in Iran such as Iraj Mirza, Eshqi, and Bahar who have released poetry in line with children's and young adults' interests and perhaps it is Iraj Mirza who has had the greatest concern in his works. Actually, children's and young adult poetry has been increasingly growing ever since the emergence of new schools, the popularization of literacy, the advent of printing press, new educational methods and novel psychological knowledge, and contact with Europe. Literary devices are considered as an artistic feature of poem. This research has aimed to investigate the literary devices present in the children's and young adult poetry of Iran. It studies seventy collections of poems of thirteen Iranian poets all of whom have been categorized in three stages and have been studied based on their literary devices. The results indicate that the presence of literary devices in the children's poetry of Iran has had an upward trend