The essential oil composition of lemon balm (Melissa officinalis L.) produced in two ecological conditions were evaluated using gas chromatographyâflame ionization detector (GCâFID) and GCâmass spectrometry (GCâMS). Thirty-three constituents, representing 91.4 ± 1.56% to 98.1 ± 0.60% of the total oil compositions, were identified. The major constituents of the essential oil were geranial (42.3 ± 1.77% to 44.9 ± 3.23%), neral (30.7 ± 1.11% to 32.6 ± 3.57%), (E)-caryophyllene (2.8 ± 1.00% to 3.5 ± 1.27%), geranyl acetate (0.7 ± 0.49% to 3.3 ± 0.15%), geraniol (0.9 ± 0.93% to 2.6 ± 0.35%), piperitone (0.6 ± 0.96% to 2.5 ± 1.81%), nerol (0.8 ± 0.44% to 2.4 ± 0.23%), caryophyllene oxide (0.8 ± 0.81% to 2.3 ± 0.55%), (E)-isocitral (0.5 ± 0.06% to 2.1 ± 0.46%) and citronellal (0.4 ± 0.52% to 2.1 ± 0.06%). The examined lemon balm essential oil was considerably rich in monoterpenoid aldehyde (citral, 73.0â77.5%).