Chemical composition of the essential oils of five Ocimum species namely Ocimum tenuiflorum syn Ocimum sanctum L. (green and purple), Ocimum kilimandscharicum Guerke, Ocimum viride Willd, Ocimum basilicum L. and Ocimum gratissimum L., obtained by a hydrodistillation was determined by GC and GC-MS. A total of one hundred three compounds were identified in the oils of five Ocimum species, of which fifteen compounds were found to be major (5.0â81.8 %) compounds. Analysis of Ocimum viride oil showed the highest amount of eugenol (81.8 %) among species besides germacrene D (7.0 %) and cis-ocimene (4.1 %). Ocimum tenuiflorum green and Ocimum tenuiflorum purple were found contain eugenol (75.5 and 33.8 %), β-elemene (9.9 and 15.7 %) and β-caryophyllene (9.6 and 21.3 %) as main compounds. Methyl eugenol (17.7 %) and β-caryophyllene (21.3 %) were also found to be an additional major compounds in Ocimum tenuiflorum purple oil. Camphor (28.8 %), β-selinene (11.4 %), α-selinene (9.6 %), maaliol (7.6 %), β-caryophyllene (6.4 %), β-gurgunene (5.2 %) were main compounds in Ocimum kalimanduscharicum oil. Similarly, Ocimum basilicum was found to contain methyl chavicol (46.0 %), trans-methyl cinnamaldehyde (20.0 %), linalool (16.7 %) while that of Ocimum gratissimum oil contain trans-methyl isoeugenol (51.9 %), cis-ocimene (18.7 %), germacrene-D (5.9 %), and β-caryophyllene (5.5 %) as major compounds. Results showed that Ocimum viride and Ocimum tenuiflorum green growing in the region rich source of oil (1.0 and 1.8 %) and eugenol (81.8 and 75.5 %) as compared to Ocimum tenuiflorum purple (33.8 %).