Purpose: In this research, essential oil (EO) compositions of the dried and fresh aerial parts of Rosmarinus officinalis cultivated in the reearch field in Selcuk University Medicinal and Aromatic Plants Department Area in Konya and collected from Mersin was investigated. Material and Methods: EO was distilled by using Clevenger type apparatus for 3 h and the chemical compositions were detected in GC-MS. Results: Although, the oil yields of the collected rosemary was determined to be 0.4 ml (in fresh) and 0.6 ml (in dried) aerial parts, the yields of the cultivated plants for fresh and dried parts were 0.32 ml (in fresh) and 0.9 ml (in dried), respectively. In this research the differences with respect to composition and components were determined between the cultivated and collected plants. On the other hand, in this study, it was also determined that the EO compositions varied with respect to be fresh or dry of the plant parts. While there were 67 and 55 of EO compositions were observed in the fresh and dried parts of the collected marjoram, respectively; in the cultivated plants there were 46 (in fresh) and 79 (in dried) components detected. Conclusion: In this study, it was observed that the major EO compositions were camphor, 1.8-cineole, borneol, α-pinene, linalool, verbenone, bornyl acetate, limonene and camphene. The objective of the study to detect the differences between the EO compositions varied according to be the plant fresh or dry and collected or cultivated.