Bayramî-Melâmî sheikh and sufi poet Hüseyin Lâmekânî lived in the end of 16th century with the beginning of 17th century. His birth date is unknown, but the date of death of Lâmekânî is 1035/1625 according to the date couplets written about his death. The poet, used the pseudonym Lâmekânî, wrote sufistic treatises and letters as well as poetic works such as Dîvân and the translation of Esrâr-nâmah. Hüseyin Lamekani’s has been also treatises explaining the hadith "Kulllu shay'in yarci'u ilâ aslihî" written in verse and prose mixed. A copy of the treatise is in the journal where the poet's Dîvân is located. The other treatise was registered under the name Risâlah of Hüseyin Lâmekânî where manuscript in the Ankara National Library. In these treatises, in the context of the idea of unity of existence, the subjects of God, the universe and existence are explained with religious and mystical evidences. In this study, the text of Hüseyin Lâmekânî's Risâlah fî Kulli Shay’in Yarci‘u Ilâ-Aslihî was published and simplified. In addition, in the context of works, Lâmekânî's understanding of unity of existence has been examined.